I read Clockwork Prince a few days ago and it was touching and heartbreaking, I had to write something. I hope you like it. :)

My Greatest Sin

After a tiring day of training and a tranquil moment playing his violin, Jem finally lied down on his bed. Right before falling asleep he began to feel strange; there was a clench in his heart and his breathing fastened. It took him a short moment to realize the fear and pain was coming from Will.

But Will is sleeping, Jem thought, confused. He remembered Will saying at dinner he would go rest right after. Had he lied and left the Institute?

Jem jumped out of bed, and on bare feet, he left to verify if Will was in his room or somewhere else, in need of his help. He was so concerned he forgot to knock on the door before entering.

Under the thin moonlight that came through the window, he saw a body laid on the bed and he sighed in relief. But the feeling didn't disappear, and as he approached Will he saw his parabatai with covers pulled down to his waist and his chest moving up and down quickly. Will's face was sweaty and his mouth moved but no sound came out. However the silver-haired boy was able to understand what Will was saying. Jem, Jem, Jem...

"Will." A gentle voice and light touch on his shoulder woke him. With blood running fast through his body he sat up as a reflex, only then to recognize Jem standing in front of him.

It was just a dream. Will took a deep breath, trying to normalize his breathing.

Jem sat on the bed next to him. "Did I disturb your dreams again?"

Worst than having a nightmare was having the same nightmare over and over again; Jem dying.

Will shook his head. "Charlotte was there too, and Henry and Jessie. Everyone I care about was dead," he confessed, looking down.

Jem brought a hand to his damp hair and pulled him closer until his head rested on his parabatai's shoulder.

As soon as he closed his eyes Will travelled back into the dream. He was running from something, he didn't remember what, neither he knew where he was; all he saw were big trees in the dark night. Looking to the irregular path to see where he put his feet, he saw someone lied on the ground but he didn't stop to see who it was. Then he passed by another body and this time he recognised Jessamine by the parasol in her hand. Right ahead he saw another two bodies, one at each side of him; he saw Henry and Charlotte's faces with lifeless eyes turned to him. With tears clouding his sight, he didn't look back at them or at his purser.

He found Jem running in front of him. At least I still have Jem, he thought. Then the boy began to slow down and coughed violently until he fell on the ground. Will reached him quickly, kneeling next to him and holding his head.

"Will," he said, spilling blood from his mouth.

"Jem, hold on. I'll get you out of here." Will slid an arm under his parabatai's feverish head.

"You have to run. Leave me, Will." Jem had another coughing fit.

"Never," he said with the throat compressed as if someone was strangling him. "I can't." He stood staring at Jem's grey eyes as a weight grew in his chest, making it difficult to breath and every beat of his heart sent a jolt of pain. Jem's eyes suddenly lost their light and he felt so empty, despite the weight and pain, as if his soul had been ripped apart and the half with all the love and happiness had vanished.

"Jem, no," he murmured as tears fell. "Jem... Jem... Jem..."

Will opened his eyes and got out of bed quickly, leaving Jem with the left hand that was caressing his hair lifted. "I have to take a walk. I need to clear my head." He grabbed the pants on the back of the chair to change for the flannel ones he was wearing.

"In this weather?" Jem stood up and gestured to the window. The rain was heavy outside. "You will get sick."

Jem's concern was touching as always but at worse he would get a cold. "Then maybe you'll finally beat me in the sword training." He showed a little smile.

"If you get out, William, I swear I'll drop Church on you while you sleep."

If it was Charlotte telling him that, she would most likely have a hand on her hip, but Jem was always apparently calm; the only changed were his eyes that now were slightly narrowed and his gaze was intense.

Will walked towards him. "Then stay with me tonight, James."

Jem's eyes softened and, after a moment, he nodded.

They laid down under the covers, facing each other. Will remembered when he was a little boy and sometimes climbed to Ella's bed in the middle of the night because a strange sound woke him up. She would always tuck him in and never complained, but he was always a bit uncomfortable. Now with Jem, it felt so natural, despite it had never happened before. When he looked at Jem he didn't see another person, he saw himself. Jem was part of him.

"What would I do without you, Jem?" He had kept everyone at distance for their safety. What if he had done the same to Jem? How many injuries he would now have, although he probably would have died long ago?

"What will you do when I'm no longer with you, you mean."

Jem knew that was his greatest fear. "You're my friend, my parabatai, my family. Without you I'm dead, Jem."

"No, you won't. You think you'll be alone, but despite your bad behaviour, Charlotte, Henry and Jessie still love you." Will closed his eyes, remembering the demon's curse and hoping it wasn't true. "I know you better than anyone, despite your secrets, and I know you're strong and you can continue being a Shadowhunter without me."

Will shook his head, remembering his dream. "I can't take it. All that emptiness and pain."

"You'll have to, Will." Jem leaned his forehead on his. "I don't want the pain of my absence to be your only memory of me. Promise me you will find a way to carry on with your life and make it as happy as possible."

"I can't think about a future without-" He touched Jem's face and the words stopped at his tight throat, so he chose a different path. "Without having a stronger memory than your death," he said in a whisper.

"You know we can't. The law forbids it." Jem's warm breathing hit his face. "You may be reckless sometimes but you don't break the law."

"The law may control what I do, but not what I feel. We're alone here, no one will know. Whether the expression of it happens or not, it won't change the love we feel, so why not?"

Jem was silent for a moment, and Will began to think he hadn't convinced his parabatai, but the Jem spoke. "Alright," he said to Will's surprise. "For I prefer break the law than break your heart."

The small space between them disappeared when Jem placed his lips on his. They were soft and tender like everything in Jem.

From the day Jem came to the Institute, they had become close friends despite his rude manners towards the dying boy with silver hair. After the parabatai ceremony their union was even stronger, and soon his feelings took a slightly different direction. He never talked about it with Jem, because if their destiny wasn't what they had now, it would destroy their relationship. But a month ago, after an unexpected fight with a demon, Jem was injured in the head and he was so fatigued for not taking the yin fen that day, he collapsed. At the Infirmary, while Jem was unconscious and Will counted his breathings, he confessed the love he had for his parabatai, more than friendship or brotherly love. After Jem recovered, he told Will he had heard his words and that he felt the same, but there was nothing they could do; the law forbid romantic relationships between parabatai.

It was the first time Will felt what he had wondered for some time; kissing Jem. He played with the smooth silver hair as Jem traced a vigorous hand up and down his back and gripped his white shirt when Will deepened the kiss.

He slipped a leg between Jem's and ran down the hand to the bottom of Jem's shirt, lifting it to touch the warm skin underneath. He slid up the fabric, desiring to take it out of the way, but it didn't pass the chest, so Will ripped it open. With the exposed body of his parabatai, Will kissed Jem's neck, making him fall on his back.

He wanted to make a comment about wonderful scent and taste of Jem's skin, but as the cause of it was the yin fen, Will repressed it. He heard Jem's irregular gasps as he trailed a hand by his slightly muscled abdomen and to his leg.

"Are you planning in leaving a mark?" he asked breathlessly. "As if I didn't have enough yours."

Will realised he had focused on a single spot on Jem's neck, and moving back he saw a red circle on the pale skin. He rose on his knees over the bed.

"I was not complaining," Jem said.

Will smiled as he removed his shirt, sliding it over the head. "I know," he replied and pulled Jem to him by the arm, meeting his lips again. Jem's own shirt fell down his arms and they continued to retrieve each other's clothes.

They lied down again with tangled limbs and no more fabric between, touching each other's fiery and sensitive skin while hearts beat wildly. With laced arms around his neck, Jem spread his fingers through Will's dark hair, preventing from detaching from his mouth, while Will above made small movements that created friction between them.

After a while, with the increase of speed, Jem carved the nails on his back as he became tense and moaned during ecstasy. Will didn't slow down and reached the climax soon after, biting Jem's bottom lip.

He moved to the side, falling back on the mattress next to Jem and his hand accidentally got above Jem's. His parabatai held his hand while the regulated their breathing.

Then they turned to each other, both grinning and thinking in saying those three little words, but Will was able reduce them to two. "My Jem."

"My Will," Jem replied.

He pulled Jem closer, rolled back and Jem laid his head on his chest. He kissed the sweaty silver hair.

While Will quickly fell asleep, Jem couldn't; his mind was too agitated. Now more than ever, he had to prepare Will to live when he was no longer with him, he thought, staring at the ceiling. Or else when he dies, he'll take Will with him. And it wasn't fair.

Too disturbed, suddenly Jem turned to the side to make his thoughts vanish. He closed his eyes and tried to calm himself, focusing on his breathing.

Then he felt Will leaning against his back and sliding and arm around his waist. Jem grabbed once again his hand touching his heart and smiled. If he was blind, he would still recognize Will for the sound of him moving, for his familiar scent, and now for his gentle touch. Their souls were tied and Jem was sure they would meet again after this short life, whether it was in the afterlife or in a new life.

"Jem, you're my greatest sin," Will murmured sleepily. "But I no longer feel guilty of it."

For years he tried relieve Will from the weight he carried every day, thought perhaps Will would share it with him, and when Jem believed it would never happen, hope came. If a small part of Will's weight had been lifted, maybe he could make it disappear completely. With that thought in mind, Jem fell asleep.

THE END