Note: Arpeggio of Blue Steel is an anime that was done by the studio Sanzigen and is based on a manga by Ark Performance.

Captain Gunzou was a young man, who was the Captain of a large ship. He wore a black suit and rarely wore a captain's hat. Gunzou was often accompanied, by a small, but helpful crew. Gunzou and his crew often used the ship, to deliver important products, across the ocean. They had a good amount of business, during their first year of work. Gunzou was a brave, confident captain, who supported his crew and treated them like friends.

However, Gunzou's life wasn't perfect. It was hard for him to explain, but he felt like his life was missing something important. After work, he'd often stare at the night sky, while pondering things about his life.

The day had finally come, when Gunzou's crew would get to return to land. The crew had no assignments or deliveries, to take care of, so they planned on staying land, for a while. Some of the crew members had been interested, in trying out other careers, so Gunzou knew a few of them wouldn't return. After Gunzou drove the ship to the dock, the crew started getting off the ship.

Sou Oribe was Gunzou's best friend and was one his crew members. After getting on the dock, Sou looked at Gunzou and asked, "What are you planning on doing, old friend?"

Gunzou answered, "I'm going to stay on the ship, for now, and see how things go from there."

Sou asked, "Are you ever going to leave that ship?"

Gunzou answered, "I don't know. I still have this feeling, that there's something in the ocean, that I have to uncover."

Sou replied, "Look, I know you have this sentimental feeling, that there's something in the ocean, that you're destined to find. However, most of the crew don't feel the same way."

Gunzou said, "I know. I've overheard them teasing me. I also overheard you defending me and I appreciate it."

Sou replied, "It's what friends are for. However, are you going to keep hanging around the ocean, to find something, that you don't know anything about?"

Gunzou put his hands in his pockets and stared at the ocean, while saying, "My career has been going well and my life hasn't been bad. However, I know there's something missing and I think I'll get what I'm seeking, by staying in the sea. Besides, I feel more at home, at my ship, than my house."

Sou raised an eyebrow and said, "So, you're going to stay here, by yourself, for a few weeks?"

Gunzou replied, "That's the plan, at least for now."

Sou responded, "I see." Sou walked closer and shook Gunzou's hand, while saying, "I hope you find the thing, that makes your life feel complete."

Gunzou replied, "Thank you. Before you go, can you answer one question?"

Sou said, "I think so."

Gunzou asked, "Do you think I'm strange?"

Sou answered, "Yes, but that's what makes you a unique individual."

Gunzou smiled and said, "Thank you."

Sou replied, "I'll visit you, in a few days. For now, enjoy yourself, Captain." He saluted Gunzou, before walking away.

Meanwhile, a young woman, named Iona, was entering a clinic. She had an appointment, with Kamikage, a therapist. She was wearing a blue dress, the only dress she had ever worn. After getting inside, she sat down and quickly became distracted, by a toy ship, that was one of the toys, from the children's' waiting area. She picked up the ship and hugged it, while a tear poured down her eye. Some of the patients saw Iona and were a little weirded-out, but none of them spoke to her.

Eventually, Kamikage was ready, so Iona entered his office. She looked around, at Kamikage's very clean and organized office. She saw several pictures, of the ocean. A light smile came upon her face, while asking, "Are you a fan of the sea, sir?"

Kamikage answered, "I used to have an office job, involving ocean-related business. During that time, I've met several captains and have even climbed aboard a few ships." Kamikage kept a picture, of each of the captains he met. One of them was Gunzou. Gunzou and Kamikage occasionally had heated discussions, but they got over their differences, shortly before Kamikage quit that job and became a therapist.

Iona sat down. She looked nervous and shy, while saying, "Thank you for meeting with me, Kamikage. I have issues, but people just think I'm crazy and make jokes, when I explain myself."

Kamikage replied, "You don't need to worry about that, while you're in here. Before I started working in this clinic, I briefly worked at Arkham Asylum. I had to learn, to take every case seriously, even the craziest-sounding things."

Iona said, "I've lost a lot of friends, by revealing what I really am."

Kamikage got out his notepad and straightened his glasses, before saying, "I'm truly sorry that happened. However, I won't be able to give you my assistance, until you stop being vague and tell me what's going on."

Iona briefly pondered the notion, of telling Kamikage the truth. She hadn't met anybody, who believed what she had to say. However, she felt it would be wasteful, if she didn't make any kind of attempt, to explain her case. She said, "You see, I'm not human."

Kamikage assumed Iona imagined she was something inhuman, in a metaphorical sense. He said, "So, you see yourself, as something else?"

Iona answered, "I have the appearance, of a human, but I am not a person."

Kamikage asked, "What do you think you are?"

Iona answered, "I'm the Mental Model, of the I-401."

Kamikage was knowledgeable, when it came to ships, so he knew the I-401 was a ship. He felt deeply confused, why anybody would claim to be a ship, from a random part of history. He said, "Allow me to ask you something: Were your ancestors involved in any ship-related business?"

Iona replied, "I've never had ancestors, because I was never born. I was created. I don't even know who my creators are."

Kamikage looked baffled, while asking, "How old are you?"

Iona answered, "I don't know my age."

Kamikage asked, "Where do you live?"

Iona answered, "I live in a hut, that has a view of the sea."

Kamikage took a moment, to try to find the right way, to word himself. He said, "So, you think you're a ship?"

Iona answered, "I'm a part of a ship."

Kamikage asked, "Do you mean that, in a literal sense?" Iona nodded. Kamikage asked, "You truly believe, that you've never been human? You think, that you're the Mental Model, of the I-401?"

Iona answered, "Yes I do. I only have fleeting memories, of the time, when I was on that ship."

Kamikage started remembering, that Gunzou's ship was the I-401. However, he didn't tell Iona that, because he feared that'd lead to bad circumstances. Iona claimed some of the strangest things, that Kamikage had ever heard. If he wanted to, Kamikage could call her a crazy person and make fun of her. However, he didn't have the heart, for such childish disrespect. He tried to word himself, in a delicate way. He said, "Instead of trying to find some old ship, I suggest finding a place, where you feel at home and can be yourself."

Iona asked, "What place would give me those feelings?"

Kamikage said, "I believe you're the one, who has to determine that."

After her appointment was over, Iona figured she better go to the place, that felt like her true home: The ocean. She got onto the dock and stared at the ocean, while saying, "It's about time, that I go home." She placed her dress on the dock and jumped into the ocean. She swam in the ocean, for a few minutes. Afterwards, she stood around, while looking at the sky. She had fond memories, from her time as a mental model, of staring at the sky. The sky was the most beautiful thing she had ever seen, apart from the ocean. While in a directionless mood, she continued swimming. She knew she wanted to be in the ocean, but she didn't know where she wanted to go.

Iona tried to get her mind off of all the stress and confusion, that she had been dealing with. She took a long look, at the ocean she was standing in and the pretty sky, that was above her. The view was pleasant and relaxing. However, it was so comforting, that Iona's mind started drifting off. Her eyes started to close.

Captain Gunzou was in his ship and was by the area, that Iona was in. Gunzou stared at the ocean, while still pondering about his life. However, he stopped focusing on that, when he noticed somebody was in the ocean. Gunzou saw that Iona was asleep, standing up. He looked concerned about her. A moment later, Iona started walking in her sleep. She accidentally tripped over a small rock. She started falling down, so Gunzou quickly jumped into the ocean. He said, "I gotta save this person, before she drowns." He swam to her and grabbed her. He looked around and said, "There's nobody else, that's around this area. She must of come here, by herself. I'll have her sleep in one of my ship's rooms, for now." Gunzou returned to his ship, while carrying Iona.

When Iona woke up, she was on the ship. Her head was laying on a pillow and she was covered in blankets. Iona looked around and asked, "What's going on?"

Gunzou walked in and said, "Hello, miss. I'm Captain Gunzou. I found you in the ocean, asleep. You were about to drown, so I picked you up. I don't know who you are or where you live, so I put you in a room, that one of my crewmates usually sleeps in. You've been asleep, for about two days."

Iona replied, "I see. Thank you, for your heroic rescue."

Gunzou responded, "You're welcome. However, before I can give you further help, you'll need to give me some information."

Iona shyly replied, "I could tell you the truth, but nobody seems to believe the things I say."

Gunzou responded, "I'm used to that, so go ahead and explain yourself."

Iona replied, "The thing, that I'm about to tell you, will sound absurd, in the eyes of most people."

Gunzou responded, "I'm open-minded."

Iona took a long pause, before saying, "I'm Iona, the Mental Model of the I-401."

Gunzou looked shocked, while replying, "The I-401 is my ship. Since you didn't even know where you were, you must not be making stuff up. You must know information, about my ship."

Iona responded, "I only have vague memories, of my past, but I remember being on this ship. It looked much different, back then. I was this ship's human avatar. However, I am not a human, despite my appearance."

Gunzou was deeply surprised, by what Iona was telling him. He said, "I've dealt with other ships, that have mental models. I've interacted with a few. They were created, to serve the role of a human, minus the emotional baggage."

Iona replied, "You're the first person I've met, who knows what mental models are."

Gunzou said, "Mental models are a well-known concept, by the government and ship captains, such as myself. However, the government is extremely reluctant, to let the public know about them. The government's secrecy is justified, this time. If the mainstream media knew about the mental models, lots of researchers would try to abduct your kind, for their highly-questionable experiments."

Iona said, "So, I'm not crazy?"

Gunzou replied, "You are strange, but strange is an attribute, that a lot of unique people possess."

Iona asked, "Does that mean I truly am your ship's mental model?"

Gunzou answered, "That's the only explanation, that would make sense. My ship has been missing a Mental Model, ever since I inherited it from my father. Somehow, you must of gotten separated from the ship, during my father's last mission."

Iona asked, "Your ship hasn't had a mental model, this entire time?"

Gunzou said, "Yes, but it hasn't been a real problem. Most ships don't a mental model. It's something, that only the most advanced ships obtain."

Iona had a guilty look on her face, while replying, "I'm sorry, Captain, for not being here, where I was supposed to be."

Gunzou gently responded, "You don't need to apologize, Iona. You received memory loss, after you got separated from the ship. Since my father and his crew never returned, everybody, who knew you, is gone."

Iona replied, "That means I no longer serve a purpose, unless you're in need of my help."

Gunzou said, "Iona, I want you to stay. I believe you will benefit this ship, since you're a mental model. On a more sentimental note, I want you to feel at home. I'm a human, yet I feel at home, when I'm on this ship. I believe you'll feel the same."

Iona smiled and replied, "Thank you, Captain."

Gunzou handed Iona her dress and said, "I found this dress, on the dock. I'm assuming it belongs to you."

Iona replied, "Yes it is. I've never seen this outfit, at any store."

Gunzou responded, "It's a special type of dress, that only mental models wear. The dress was made to look similar, to human dresses. Since mental models are a secret, the government wants your kind, to dress like humans."

Iona slipped on the dress and said, "I see." She stood up and asked, "How do I look?"

Gunzou looked at her and answered, "You're a very pretty woman."

Iona replied, "Thank you, but I was trying to ask, if I look like a proper mental model."

Gunzou responded, "Yes you do."

Iona asked, "Where are your crewmates?"

Gunzou said, "Some of them are taking a break, while others are pursuing different careers. I was pretty lonely, until you came along."

Iona shyly replied, "I'm probably not good company. After all, I'm not human."

Gunzou put her hand on her shoulder and said, "To me, you are human."

Iona had a confused look on her face, while asking, "What does that mean?"

Gunzou said, "Although you aren't human, you have the human emotions, that other mental models lack. The others, that I've spoken to, are completely robotic and resemble a machine, in terms of personality. However, you have emotions. You have curiosity, guilt, and an adventurous nature."

Iona looked upset, while replying, "Mental models aren't supposed to get emotional. They're supposed be emotionless, so they can obey the commands, that humans would never agree to."

Gunzou responded, "That's true, but I like that you have emotions. It makes you special and it gives me someone, who I can communicate with."

Iona bowed to Gunzou and said, "I'm ready to obey any command, that you wish me to do."

Gunzou calmly replied, "Don't be so formal. I do enjoy being the Captain, but I never want my crew to feel like sidekicks. I consider all of my crewmates friends and since you are now a part of my crew, you have become a friend of mine."

Iona responded, "My other friends thought I was insane, for claiming to be a mental model."

Gunzou replied, "Your other friends were insane, for abandoning someone so wonderful." Iona got closer to Gunzou and kissed his lips. Gunzou looked shocked, while asking, "Why did you do that?"

Iona explained, "My former friends told me, that a kiss was the proper way, of thanking someone you love."

Gunzou said, "Um, that is true, but a kiss is for people, who are in a romantic relationship. Do you know what romance is?"

Iona answered, "I have fleeting memories, of people telling me about it."

Gunzou said, "A kiss was a bit much, considering we barely know one another."

Iona replied, "I'm truly sorry, for the kiss. I hadn't felt such strong feelings, for anyone."

Gunzou responded, "You don't need to be sorry, but kissing isn't something you should do, until you get a boyfriend or girlfriend."

A thought popped into Iona's head. Iona was in a more playful, happy mood, than ever before, so she made a cute face, while asking, "Do you have a boyfriend or girlfriend?"

Gunzou answered, "No, I've never been in a romantic relationship."

Iona said, "I'm just mentioning this, as a trivia fact, but I'm single."

Gunzou looked amused, while replying, "I assumed so."

Iona asked, "Did you hate the kiss I gave you?"

Gunzou answered, "No, it felt nice." Iona kissed Gunzou, for the second time. Gunzou asked, "Why did you do that?"

Iona said, "I'm not an expert, on human culture, but I've learned people like things, that feel nice. I assumed you wanted another kiss. Did I guess wrong?"

Gunzou answered, "I'm afraid so."

Iona noticed Gunzou's face was getting red, so she nervously said, "Captain, why is your face turning red? Are you getting some kind of sea sickness?"

Gunzou looked embarrassed, while replying, "No, I'm blushing."

Iona said, "Captain, would you ever lie to me?"

Gunzou replied, "First off, please call me Gunzou, when we're not on a mission. Second off, no, I wouldn't lie to you."

Iona asked, "Do you like my kisses?"

Gunzou took a long pause, before sighing and answering, "Yes."

Iona asked, "Then why do you disapprove of them?"

Gunzou answered, "Because this is a very weird situation, for me to be in."

Iona had a sad look on her face, while saying, "It's because I'm not a human. I'm a failure, when it comes to being a proper mental model. I'm never supposed to have these feelings."

Gunzou replied, "The fact, that you're not human, isn't a problem."

Iona asked, "What is the problem?"

Gunzou answered, "We don't know much about each other."

Iona replied, "I know I've been around, for at least two decades, and I've never felt such strong happiness, until this day."

A realization popped into Gunzou's head. For a long time, he felt something had been missing. He realized Iona was the thing, that his life had been missing. He said, "I finally found you. This may sound strange, but ever since I became a successful captain, I felt like my life was missing something. I didn't know what it was, but I kept searching for it. You were the thing, that I've been looking for."

Iona replied, "Thank you, Captain. I'm excited to be your mental model, as well as your girlfriend."

Gunzou responded, "Iona, you aren't my girlfriend."

Iona asked, "Would you rather date someone else?"

Gunzou answered, "No, but it'd be strange, if I date you."

Iona asked, "Didn't you claim, that strange things can be wonderfully unique?"

Gunzou said, "Yes."

Iona asked, "Am I pushing my limits, Gunzou?"

Gunzou answered, "I'm afraid you might be, but let's not focus on that." He tried to change the subject, by saying, "Other mental models don't eat. Do you ever eat anything?" Iona shook her head. Gunzou jokingly said, "Then it'd be cost-effective, to date you."

Iona smiled and asked, "Then what are we waiting for?"

Gunzou said, "One of my crewmates will be coming, in a short while, to dine with me. Since I'll be having company, I better clean myself up."

Iona replied, "Since you're the Captain, I avoided telling you, that you smell rather rough."

Gunzou responded, "I haven't been around other people, for the last few days, so I didn't take a shower."

Iona replied, "I'll also take a shower."

Gunzou said, "After I take my shower, I'll show you where the bathroom is."

Iona asked, "Bathroom? Who would shower in a toilet? If you do, I won't judge, but I'm going to take a real shower."

Gunzou raised an eyebrow and asked, "A real shower?" Iona jumped into the water. Gunzou ran by and said, "Iona, people bathe in bathrooms, not in the ocean. It's impractical, to bathe in there."

Iona replied, "I always bathe in the ocean. I would never bathe in a toilet."

Gunzou said, "People bathe in bathtubs, not in toilets."

Iona replied, "I don't know what a bathtub is."

Gunzou asked, "Are you wearing your dress, while bathing?"

Iona answered, "It's how I've kept it clean."

Gunzou said, "If you want to bathe in the ocean, be my guest. However, I'm going to use a real bathtub." Gunzou went into his bathroom and took a shower.

After Gunzou finished his shower, he got on a white suit. Iona got on the ship. Gunzou walked up to her and asked, "How do I look?"

Iona answered, "Hot."

Gunzou looked at Iona and said, "Your dress is soaked. You shouldn't shower, with your clothes on, anymore."

Iona asked, "Why?"

Gunzou explained, "Your body won't get fully clean."

Iona asked, "Does that mean I've never taken a proper shower?"

Gunzou answered, "I guess not."

Iona replied, "I've probably been getting a lot of things wrong."

Gunzou put his hand on her shoulder and responded, "Yes, but you've also been doing a lot of incredible things, that no other mental model has done."

Iona asked, "So, you'll let me stay, despite my flaws?"

Gunzou answered, "Of course I will."

Iona could feel special feelings, from the bottom of heart. Her mouth was about to utter three words, that she had never said to anyone. She said, "I love you." She paused and asked, "Do you love me?"

Gunzou tried to avoid giving a straight answer, so he said, "I care about you."

Iona replied, "That's not a real answer and you can't lie, so you'll have to be honest."

Gunzou said, "Yes, I love you."

Iona looked intrigued, while asking, "What type of love?"

Gunzou thought about it and replied, "It's hard to describe, but it's a type of love, that I'm unfamiliar with."

Iona smiled, while saying, "I think you want me to be your girlfriend."

Gunzou replied, "Let's not discuss this topic."

Iona walked closer and said, "Gunzou, I've spent years, being lonely, confused, and feeling lost. Thanks to you, I've found a purpose and I've also found happiness." She mad a mischievous grin on her face, while saying, "I'm going to be loyal, but I'm also going to do things you'll claim you don't like, but I know otherwise." She kissed Gunzou, for the third time.

Gunzou said, "Iona, you're quite sneaky, especially for a mental model."

Iona replied, "I'm afraid that's true." She started feeling guilty, while saying, "I shouldn't be kissing you. It was wrong of me."

Gunzou said, "It's okay. You shouldn't be guilty. I'm embarrassed to admit it, but your kisses felt lovely."

Iona shyly asked, "Then do you want to give me a kiss?"

Gunzou also felt shy, while saying, "I don't know."

Iona replied, "I won't force you. Do what makes you feel happy."

Gunzou blushed, while responding, "You make me happy." He kissed her, which made her feel overjoyed.

A few minutes later, Sou got onboard. He walked up to Gunzou and quickly noticed Iona. Sou said, "Greetings, Captain. Who's this person?"

Iona said, "I'm Gunzou's girlfriend."

Gunzou looked at her and replied, "I didn't make our relationship status official. However, I suppose you are the love, that my heart's always been seeking." Iona hugged Gunzou, while Gunzou explained to Sou, "She's my ship's mental model."

Sou asked, "You're dating your ship's mental model?"

Gunzou said, "You could say that. Even you will probably start teasing me."

Sou shook his head and replied, "I can't deny this is strange, but I'm glad you found the thing, that makes your life feel complete."

Gunzou responded, "Thank you." Gunzou and Sou started having dinner, while Iona continued hugging Gunzou. Gunzou and Iona had never had a stranger day, but they also hadn't experienced a more wonderful day. Gunzou and Iona had both felt they had to find something, that would make their lives worthwhile. They had more happiness, than they had ever anticipated, thanks to the love they had for each other.