Disclaimer: I do not own PJO or the song "I'm Sorry" by Gummy ft. T.O.P.

A/N: My friend Nicole was singing along to this song the other day. It reminded me of the pairing Thuke, so I decided to write this. The fic is based on the song "I'm Sorry" by Gummy, a Korean pop artist.

~ SKYE :]

Luke Castellan made his way down the dark corridor of the Titan's headquarters. The corridor was gloomy and dark, the only source of light being the small fire torches which lined the walls. The fire casted eerie lights that danced over the many different monsters as they walked down the hall way.

Luke was wearing a thick dark cloak. He had the hood pulled over his head and his shoulders were hunched. He walked quickly towards his room where he could find solace in being by himself.

Today was the day he would tell her, he decided. Today he would say sorry.

He strode into his room, slamming the heavy oak doors shut and bolting it. Luke hated this place. This place was a sinister, dark place. The Titan's headquarters would never be his home. It just didn't feel right.

Luke pulled his cloak off before walking to a large mahogany desk. Brushing aside all of the mess on the table, he pulled out some paper and chose a ball point pen from an open drawer. Then, he began to write.

His brow furrowed and his face contorted into that of complete concentration.

Dear Thalia, he wrote, before pausing, his pen hovering above the paper. I'm sorry. I've been a fool. I wish I could –

Luke stopped again before scribbling out what he wrote. He growled and crushed the paper into a ball then hurled it at his door as fast and as hard as he could. The paper ball bounced harmlessly off, falling softly to the floor.

Dear Thalia, he began again.

When the morning comes, will I be able to see you again? I promise that I'll love you like the first time we met.

I remember the first time I met you. Out of all the other girls, you were the one who caught my eye. You were (and still are) beautiful, like the main character in an old time movie. I couldn't get you out of my mind. You do remember those movies, don't you? Those black and white ones we used to laugh at so much.

I'm sorry I promised you promises which I could never keep. Remember when I promised that you, Annabeth and I will be a family forever? I also promised that I would never let anything happen to you two. I'm sorry I let you down and broke those promises. You turned into a tree because of me and you and Annabeth both got hurt. I'm sorry I couldn't protect you.

I hurt you and gave you scars when I went to the Titans' side. I abandoned you and let you down again. I know my sincere apology is late.

After you read this don't try and look for me. Tomorrow Kronos is going to fully take over my body. I won't be me anymore. If you see me, don't get in my way, please. What you see will not be me. It will be him. By the time you read this, I will probably be good as dead.

Please forgive me. I'll give you all my tears and even beg on my knees. Just give me a chance to put things right. When the time comes, I'll put things right. I promise you. And this time, I'll keep that promise.

I know those past few days and weeks have been agony for you, so I won't burden you anymore. I'm going to set things right.

The tears you've shed alone and all the pain and hurt I've caused you, I'm sorry. No matter how much time passes us, I'll never forget you. Thalia, if we ever meet again and if you still want me in your heart, I'll promise you that I'll hold you again like those days back when we were happy.

I'm sorry for hurting you. I'm sorry that I couldn't just forget you. I'm sorry for doing nothing for you. I'm sorry but today I wanted to see you for one last time.

I'm sorry, I love you.

- L. Castellan.

Luke stopped writing and looked back at his letter. He had tried to write down what he felt in those words. It didn't exactly come out the way he planned in his head. Maybe a little to the soppy side, but it didn't matter. As long as the words were out and told to Thalia.

He carefully folded the letter up and slipped it into the pocket of his pants. Luke then picked up his cloak which was discarded on the ground earlier. He put his cloak on and walked to the balcony of his room. Grabbing the pipe next to the wall, he half slid and half climbed down to the ground. Then he removed a shiny trinket that Kronos had given him a few days ago and held it in the palm of his hand. He concentrated on an image in his mind of a certain pretty blue-eyed girl with spiky raven black hair. A small warp hole opened adjacent to him. It showed a beautiful forest crowded with silver tents. The warp hole's image rippled ever so slowly in the night breeze as if inviting him to step through.

Luke did step through. As soon as he did, he found himself in the middle of the forest with the tents surrounding him. He walked softly, his heavy boots making no noise, towards a tent which had the symbol of a lightning bolt emblazoned on it. He unzipped the tent to find a sleeping Thalia Grace, sleeping peacefully in her sleeping bag.

Luke's facial expression softened. His usual scowl was replaced with a soft tenderness only reserved for the punk-like daughter of Zeus. He slowly walked over to her sleeping form, and as if in a trance or a dream, he slowly bent down and pressed his forehead onto hers. The gesture brought back painful memories of how they used to greet each other in the past.

He pulled away from Thalia to slip the note under her pillow. Then he stood up and walked to the entrance of the tent. Luke couldn't help but glance back once more at her. She lay asleep with no frown or glare on her face. The glares and frowns replaced the small smile she would usually give him today. Luke took this chance to memorise her – her wild spiky hair, her pink lips and the light dusting of freckles which she despised so much yet he loved. Sighing softly, he made his way out of her tent and slowly zipped the entrance closed.

Goodbye, Thalia. I'll miss you.

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Thalia woke up the next day with a mighty headache. She had the weirdest dream last night in which Luke appeared in her room and told her goodbye. How very peculiar, she thought.

Today was the day, though. It was the day of the final battle between the Gods and the Titans. Thalia and her Hunters had been called by her cousin, Percy Jackson, to help them.

She slowly got up from her sleeping bag, not noticing the crinkled letter under the pillow.

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After the battle, Thalia had learned that Luke sacrificed himself in order to defeat Kronos. Luke was the hero of the Great Prophecy, and despite feeling angry at him for betraying her and her friends, she was happy that he had finally put things right.

Thalia was sad however that she wasn't there to see him for one last time. She had cursed Hera to the deepest pits of Tartarus when her leg got caught under a Hera statue aimed for Annabeth.

Later at his funeral, Thalia let one tear slide down her cheek. Luke was wrapped in a green and white shroud. She had limped up to his wrapped body in her crutches and said her goodbye, remembering her brave friend.

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A few days later, Thalia found the crinkled note under her pillow left from Luke. Puzzled at what it was, she opened it and read it.

Thalia Grace finally broke. She let out a small sob and slowly let herself drop to the floor of her tent.

There, visible in the palm of her hand was the letter and here in her heart was the answer. Yes, I love you too, she thought.

She glanced down at the letter in her palm and the words flashed bright and clear, the black ink standing out from the white paper:

I'm sorry, I love you.

- L. Castellan.