Spiritimus Prime: I must've been on a caffine spree to be making this! This is the first time I've ever made a oneshot dedicated to my favourite pairing: Optimus/Arcee. This is the first oneshot of a oneshot trilogy that's going on inside my head. Since watching "Orion Pax, part 3" I got a huge inspiration boost and thought it was better to get it done now before my muse ran away crying to its mummy. Hope you like it guys and girls!

Promise Me You'll Remember

Arcee trembled violently as the images flashed before her optics. Terror gripped her spark as she saw the image of Tailgate being slaughtered by Airachnid. She wanted to scream, she wanted to wake up from this dreaded nightmare. But she was trapped in a void with the image repeating itself over and over again. "Tailgate!" she screamed, her optics squeezed tightly.

"Arcee! Wake up!"

Immediately, Arcee bolted upright, screaming her former partner's name once again. Her breathing was laboured and beads of oil dripped from the corners of her head and neck. She soon became aware that she was not alone in the room and glanced around to find Optimus sitting on her berth and looking down upon her with concerned optics. His hands were on her shoulders and it soon came to her that he had been shaking her to get her out of her nightmare.

"Optimus?" she questioned, blinking her optics. "What are you doing here?"

Optimus seemed to vent a sigh of relief before he explained, "I couldn't recharge, so I was heading down to the command centre when I heard you screaming for help and Tailgate's name. I was concerned about you, so I tried to wake you up. You didn't respond to me and I had to shake you awake. Are you alright now?"

Arcee glanced down at the ground, avoiding optic contact with her commander. She should've known that Optimus would come here out of concern for her own wellbeing. But why he decided to wake her from her nightmare was beyond her understanding. She brought her knees to her chest and leaned on them, trying to think of a way to answer Optimus' question.

When he got no response from her, Optimus placed a hand upon her shoulder and gave it a light squeeze of reassurance. She looked up at him, optics on the brink of tearing up.

"Arcee," Optimus rumbled, "tell me what is wrong so that I can help you."

Arcee looked away, ashamed. She had never told any of her fellow Autobots about the death of Tailgate at the hands of Airachnid. The only one who knew about it was Cliffjumper and Bumblebee. Both warriors had sworn to secrecy to never tell anyone about what had happened to Tailgate, knowing that even the slightest mention of her former partner would upset her tremendously.

"I don't know how to tell you, Optimus," Arcee whispered, resting her chin upon her knees. How could she tell him? "No one would understand what I'm going through... no one."

Optimus sighed quietly, not wanting to put pressure on her anymore. Arcee would tell him when she was ready. He stood and removed his hand from her shoulder, heading back to the doorway, but then stopped and glanced over his shoulder to look at her with sympathetic optics. "I actually do understand what you are going through, Arcee," he said softly. "For I, too, know the meaning of loss."

He then took a few steps forward before Arcee's voice called him back.

"Optimus, wait," Arcee called.

He stopped and looked at her, his optics soft. "What is it?"

"There is... something you should know," Arcee said, tears leaking from the corners of her optics. She heard Optimus' footsteps before she felt his warm body heat right next to her. He seemed to be waiting patiently for her explanation. She took a deep vent and explained, "Tailgate... he was more than just my former partner back on Cybertron... Back then, I had feelings for him. I loved him. We were in a relationship, but we didn't express our love in front of everyone because we were worried that the Great War would separate us from each other. However, it was during a run in with the Decepticons that we realised that nothing was to be. Tailgate was ordered to snipe a 'Con; he missed and I was forced to separate from him and engage the enemy hand-to-hand. I took the 'Con down and ended up getting lost on the battlefield. I asked for Tailgate's position and was just about to head for the place where he was waiting when I was..."

Optimus waited for her to continue.

"I was ambushed by Airachnid..." Arcee trembled at the memories, recalling how she was suspended in midair while imprisoned by the evil femme 'Con. "During my capture... she tortured me to the brink of wanting to annihilate me, but when she realised that she wasn't getting any info from me, two Decepticon troopers arrived with Tailgate in between them. He was... badly damaged and in stasis lock.

"Airachnid threatened me that if I didn't tell he attack coordinates she would offline Tailgate. I tried to tell her the truth – that I didn't know them at all. She didn't believe me and she... she..."

The memories flashed before her optics as she saw Airachnid lift a claw and gruesomely kill Tailgate. She remembered the scent of energon as it splashed across the wall, and Tailgate's body falling to the ground in a pool of his own energon. As those memories faded into the back of her processor, Arcee whispered Tailgate's name and her tears continued to fall faster, staining the berth she sat on.

"And... after Cliffjumper came into the picture and we became partners, I had eventually moved on and fell in love all over again. I had assumed that we would be together. But, alas, it was not to be when Starscream killed him... I swore I would never love again after that..."

"Arcee..." Optimus whispered, drawing closer to her, wrapping an arm around her petite waist. Arcee lifted her head and glanced up at Optimus. She was surprised to find him looking at her with optics filled with concern. She wasn't sure what to say to him. How could she tell him that since Cliffjumper went offline that she was more than hurting. She missed Cliffjumper dearly, and it hurt to even think about him.

"Arcee," Optimus said, "I know it is too soon because of your loss of Cliffjumper, but there is something you should know too."

The blue femme blinked away her tears and looked into Optimus' warm optics. "What?" she managed to say until she was silenced by Optimus, who leaned forward and he planted a deep kiss upon her lips, his own covering hers completely. She wasn't sure what to do or how to react as he held her gently in his massive hands. But then it soon became clearer as to why he was doing this.

Then, it just happened. She immediately responded in kind by wrapping her arms around his neck, pulling him closer. She soon felt his glossa attempting to slip into her mouth and she quickly granted him access. Optimus' glossa wiggled about inside her mouth, tasting every bit of it before touching her own. Her glossa replied by locking with his and they wrestled for dominance.

Arcee had never experienced a kiss like this before. It was much different compared to the usual Cybertronian kiss where it was just lips touching and then pulling away. She guessed that Optimus had done his research on human kissing.

She was shocked when Optimus gently pushed her down onto the berth and hovered over her like a gargoyle, his optics shining with a hidden passion she had not seen before. She assumed that he always kept his emotions in check and never revealed them to anyone. Not even Ratchet, his closest friend.

"Optimus, why are you doing this?" Arcee asked.

Optimus shook his head and kissed her again, taking her chin into his large hand and holding her close. Why he was doing this, he wouldn't know. He just assumed she needed to know his true feelings for her. Ever since she had joined his team, he felt a strange feeling for her, but held himself back, afraid that it was some sort of fantasy. Now, centuries later, after holding himself back for so long, he had come to a realisation that it was no ordinary feeling. It was love. Not the usual lust fulfilling emotion, but rather it was something his spark desired.

"I..." Optimus said quietly, "I have always had feelings for you, Arcee. I couldn't express myself because I was than afraid that I might hurt you, and..." He hesitated a moment before continuing. "You had gone through so much in the past and I knew you were not ready for love, especially after the loss of Cliffjumper."

Arcee bowed her head, tears falling again. "But why now, Optimus?"

Seeing her tears, Optimus wiped them away. "Because, Arcee, you need someone, someone who will not be leaving any time soon." He resumed his kiss and she accepted it without hesitation.

The blue femme accepted it because she knew Optimus was right. Optimus was strong, handsome, and perhaps unique. Why else would he be the Autobot commander? She had in the past developed feelings for Optimus. And just like Optimus, she had dismissed the thought until reality sunk in at the hands of nearly killing Starscream after he revealed he had killed Cliffjumper and Bumblebee had stopped her from delivering the killing blow.

"Arcee..." Optimus called, as though he sensed her thoughts. "I know what you are thinking. You do not want this to be because you are worried you will lose me like you lost Tailgate and Cliffjumper. Am I right?"

Arcee just nodded quietly.

"You will not lose me, Arcee," Optimus whispered, sitting on the berth and pulling her close to his chest with his big, strong arms. "I will never leave your side. I promise I will not."

"Optimus," Arcee breathed as she pressed her head against his head. "There's always a chance it can happen. I just don't want that to be you."

"There is," Optimus said, closing his optics and kissing her again, the passion growing stronger between them. "But know this: I will always come back to you, Arcee. I always will."

"Then promise me this, Optimus Prime," Arcee whispered. "If this should ever work between us, I just want to know one thing."

"What's that?"

"Promise me you'll always remember, Optimus," Arcee sighed, optics closed.

Optimus sighed and pressed deeply into the kiss. "I promise, Arcee. I promise to always remember."

Arcee didn't need to be reassured anymore. She placed her hands around his neck and kissed him deeply, passionately, lovingly. She prayed to Primus that she and Optimus would stay together for all eternity. But until the war was over, they would just have to settle with these petty night time togetherness. She couldn't argue with that, and she hoped with all her spark that it was to be.

"Be alive with me tonight, Arcee," Optimus said quietly, interrupting her thoughts.

Arcee didn't need to be told twice. She gave into him, and as they lost themselves in complete ecstasy, she sensed a disturbance sometime in the future. She didn't know what it was, but she hoped that it would not separate her from Optimus forever.