In the middle of telling a story, Will glanced sideways at Jem only to see that his eyes were glazed over, his mind no doubt very far from where they sat side by side on the roof of the Institute. 

"And then the bartender transformed into an enormous demon and ate everyone else in the bar," Will said in the same light tone, watching Jem's face for a reaction.

He got none, only a small hummed noise in response. 

"It had dozens of legs, truly quite horrifying. It told me it wanted to take me back to its lair and ravish me," he said, growing bolder in his lie.

Still nothing, only an absent nod.

Will huffed an annoyed sigh, jostling Jem from his reverie. "James."

Jem blinked. "Mmm? What?"

"You aren't listening to me."

"I'm sorry," Jem said. "I was lost in thought. What were you saying?"

"Nothing of importance," Will said, waving a hand dismissively. "What occupies you so?"

Jem was quiet. Here, Will knew better than to press. After so many years of intimate familiarity with the workings of his parabatai's mind, he knew when it was better to let Jem have his silence and when he needed to badger him for information. 

Sure enough, Jem spoke again after a long moment. "Are you familiar with the story of Patroclus?"

The name was familiar and tugged at Will. "I know that I should know him," he said. "Though I do not know why."

Jem half smiled. "What an eloquent way of admitting you do not pay attention to what Charlotte tells us to study," he said. 

Will laughed. "Why should I when I have you? You will learn it for both of us and fill me in later."

"He was mentioned in something we read some time ago," Jem continued, "About the origin and history of the parabatai bond."

"He was a Shadowhunter?" That did not feel right to Will; something about the name was not anything he had heard in the Clave before, and there was no last name to tie him to a family.

Jem shook his head. "No, he lived in ancient Greece," he said. "But he had a similar sort of bond, tied to his shield-brother with an oath before their gods and with the love they bore for each other."

"So a Greek parabatai bond, then," Will said. It sounded very much like the bond they shared.

Jem nodded. "They mentioned him in passing only. I had to look elsewhere to find much about him."

"Who was his shield-brother?"

Jem's lips quirked into a half-smile. "This name you will know. It was Achilles."

Will knew the general story of Achilles; a half god walking amongst the soldiers in Greece, fighting in the Trojan War for the honor of the most beautiful woman who had ever lived, invincible save for his heel. He was a young soldier, the best of his generation, who had lived and died a hero. 

"He was a hero," Will said. "A demigod. Right?"

Jem nodded. 

"Tell me the story," Will said, laying on his back and looking up at the sky. It was beginning to bleed red at the edges, the sun slipping over the horizon. The night would find them up here soon, but Will made no move to go back inside. He closed his eyes against the dying sunlight and listened as Jem drew a breath to speak. 

"Patroclus was born a prince," he began, "To an unpopular king and his simple wife. The boy was scrawny as a youth and not well liked by his father. When he was young, he was exiled. His father disowned him and he was forced to leave behind the life he had known and depend on the charity of another king, Peleus."

Will could hear a strange melancholy in Jem's voice, and he saw the parallel threads between the life of this long-gone hero and his own best friend. He wondered if that was why Jem was telling him this. He stayed quiet for now, content to let Jem's quiet, thoughtful voice wash over him.

"Peleus had a son Patroclus's age, another boy living in the palace, amongst a few other orphans and exiles the good king had taken in," he said. "His son, Achilles, took a liking to Patroclus despite Patroclus being a mediocre soldier and rather reserved. They took their oaths to each other not long after meeting, and it is said that Patroclus rarely left Achilles's side after that."

Will looked up at Jem, watching the light play on the sharp angles of his face. Jem was not looking at him, instead looking straight ahead at the rooftops of London. 

"They sound a bit like us," Will ventured. 

Jem nodded. "They do," he said. "Achilles reminded me of you. He was the finest soldier of his generation, as impressive as Jason or Heracles. He was gifted, destined to do great things. Unbeatable save one tiny flaw."

Will felt something in his chest tighten at the warm pride in Jem's voice. He reached his arm out and laid his hand over Jem's where it rested. Jem turned his hand over, lacing his fingers tightly with Will's and squeezing. 

"You think that highly of me?"

"I think that you are the kind of man that people write songs about and hang up in the constellations to remember," Jem said. "I think you were meant to be a Shadowhunter and I have no doubts that people will remember your name until we Shadowhunters return to ashes and dust."

Will felt as though his heart might burst. A rush of affection swelled up in his chest, threatening to spill out in a wave of truth, but no sound came out of his mouth. He swallowed past the lump in his throat and squeezed Jem's hand instead.

"What happened to them?" Will said. "You don't look like someone telling a story with a happy ending."

Jem sighed, eyes never leaving the horizon. "Heroes don't get happy endings," he said slowly. "I am hoping you will be the first. When the Trojan War began, Achilles was asked to go and fight on the side of the Greeks, who were planning to lay siege to Troy and take Helen back to her husband. He went; Patroclus was not much of a soldier, but he followed. He would not let Achilles go to his death alone. 

"There was a prophecy that Achilles would die in battle," Jem said. "Patroclus sought to prevent it or to steal more time from the gods."

"It didn't work?"

Jem shook his head. "Patroclus went into battle in Achilles's armor," he said. "He was slain. Achilles was grieving and furious and he rejoined the battle. He died not long after. Perhaps the plan would have worked, but Achilles lost something of himself when his shield-brother died."

Jem's voice had grown heavy. He still was not looking at Will, and Will could feel the darkness of night creeping up on them. This was not the first time Jem had spoken of his own death —in fact, he did so candidly and more often than Will ever wanted to hear —but it was the first time Will had seen it weigh so heavily on his mind. 

"Is that what troubles you?" he asked, sitting up. "You are worried I will follow Achilles's footsteps too closely?"

"I know you well enough to know that you would rather live for me than die for me," Jem replied evenly. "We have had that conversation enough; you know where I stand. I trust you not to do anything foolish."

"Then what?" Will prompted. 

Jem drew his knees closer to his chest, resting his arm atop them. His other hand was still clutched in Will's. He tipped his face back to look at the sky, watching the color fade as the first stars began to peer through. 

He was almost devastatingly lovely like this, Will thought. He was all angles and long, lean lines and the soft silver of his hair and eyes, gleaming like starlight. There was a softness to him here that Will did not often see. It made him look younger, more like his seventeen and a half years and less like the adult it was easy to imagine he was. 

"Their story was a tragedy," he said. "But very few people remember them both. Anyone who does remember Achilles remembers him as a hero. Patroclus is either lost to history or simply remembered as his close friend and his shield-brother."

"You pity him?"

Jem laughed. "Will, I am him," he said. "I can't tell if I feel bad for him or hope for the same fate."

Will furrowed his brow. "I don't understand."

"People tell stories of tragedy," Jem said. "It's why Greek mythologies survive, it's why people crowd into theaters to watch Shakespearean dramas where every character dies. Shadowhunters are not much different. We tell our children stories of family they don't know and of fights with demons that were fought a hundred years ago."

Will nodded, unsure where Jem was going.

Finally, finally, Jem turned to look at him. "My life has all the makings of a tragedy," he said. "And it will end that way, too. But I did not live an unhappy life. I..." He sighed, shaking his head. "I was happy for most of it. Even when I was sick, I have not been miserable, but that is how my story would be told. No one would bother to remember anything else. It would be too easy to remember that I was attacked and tortured and orphaned, that I was a lost cause for the Silent Brothers, that I was addicted and sick and died young."

"It's all true," Will said slowly.

"It is," Jem agreed. "I am an orphan. I have been sick for years. I won't live to see my twentieth birthday. But that is not my life. So I have been thinking about Patroclus," he said, "Because I think I would be content if I was remembered the same way. If my story is nothing more than a few chapters in yours, that is the part I want to outlive me. Let the tragic parts of it die with me. You have only ever been a source of light."

Will was silent for a long moment. "You are more of a hero than you give yourself credit for," he said finally, hearing his voice catch. 

Jem shook his head, but he was smiling contentedly now, leaning against Will until their shoulders brushed. Their hands were still clasped, his thumb rubbing lazy circles on the back of Will's hand. "Heroes are never happy," he said, "And I have been happy like this. With you."

"Then I am no hero, either," Will said. "Because I have been happy, too." 

Jem smiled at him, leaning his head briefly against Will's shoulder. Anywhere they touched felt warm, like their affection could completely block out the chill of the night, like magic. Perhaps it could. Perhaps their bond was magic, bending and shaping two tragedies into a few precious years of laughter and happiness and learning what it meant to love another person.

"Do you think Patroclus and Achilles met again?" Will asked. "Do you think your wheel turned and gave them another chance to be together?"

Jem looked at him for a long moment, his gaze searching. Thoughts flashed through Will's head, lightning quick and impossible to pin down. There were glimpses of a ship, flags flying along an unfamiliar shore, a man who might have been Jem in armor just slightly too big. The feeling of clothes he had never worn. The smell of the sea. The familiar sword calluses on a hand he held tightly in his.

Jem smiled. "Yes," he said. "I think they got their chance. And we wil have ours, too."