I do not own Harry Potter.

Harry was unusually quiet after getting home for Christmas vacation. Neither his mother's nor father's questions or gentle hints had gotten anywhere, as Harry just closed off more in response. So, they had dropped the subject, allowing him to brood in peace, and hoping he would come to them when he was ready. James sometimes wondered if his son found it easier to tell them things through the distance of letters rather than face to face.

Nevertheless, he didn't have to wait long. He had barely settled into his study that evening when there was a knock on the door. This was unusual in and of itself: both Lily and Harry knew they could just come in when they wanted. Puzzled and a little apprehensive, James got up and opened the study door.

Harry stood there, white-faced, with a peculiar expression. He jumped in without preamble. "Why didn't you tell me who Sirius Black was?"

James couldn't do anything but gape at him. His mind was blank with surprise.

What in the name of Merlin? How the hell had he found out? So few people knew about the finer details of what had happened.

"Who told you?" James asked numbly.

Harry scowled and shoved past him into the room. James shut the door mechanically behind them. "Not from you," he said," or anyone else who matters. I've heard the story of what happened that night from so many people and nobody thought to mention…" he broke off, breathing hard. "Why didn't you tell me?" he repeated.

I told you so, said a voice in the back of his head that sounded like Lily. She had asked what would happen if he found out from someone else.

"I didn't think it would make a difference," James said carefully, moving to stand near the desk.

"Wouldn't make a…!"

"And I don't like talking about it," James finished, talking slightly louder to be heard over Harry's words. "Or thinking about it, for that matter. It's only been three years for me, remember?" That was misleading. He suspected it would hurt just as much to talk about it even if he had lived the last thirteen years. "What exactly did you hear? Not very many people know the full story."

"I overheard Fudge, McGonagall, and Hagrid telling Madam Rosmerta about it in Hogsmeade," Harry said, and James felt a flash of anger at the three of them gossiping about something so personal to him and none of their business where anyone could overhear. Harry explained what he had overheard, about the inseparable friendship, the fidelias charm, Hagrid meeting Sirius in the wreckage of their house (something James had been unaware of), and Peter Pettigrew.

James sighed, taking off his glasses to rub at his eyes before replacing them. "Well, that is essentially what happened," he said, slightly proud of how steady his voice was. "The thing almost nobody knows is Black wasn't our secret keeper. Peter was."

Harry's anger seemed to be temporarily shocked out of him. "What?"

James nodded, tiredly. "Your mother and I were planning to use Black as our secret keeper, but at the last minute, he suggested we use Peter instead. As a bluff, he said. Only the four of us knew about the switch."

There was a moment of silence as James remembered that night. "Come on, James, this is the safest plan for all of us." Sirius had been so earnest. None of them had thought much of the plan at first, least of all Peter.

"You don't want me as your secret keeper. I'm not, I'm not strong enough."

"That's one thing we don't have to worry about, Peter. We know you'd never betray us."

But Sirius had been determined, persuasive.

James would never forgive himself for putting Peter in that position.

He sat down, suddenly very tired. "When Lily and I woke up, we thought Peter was the one who betrayed us," he said.

"What changed your mind?" Harry said, quietly.

"The fact that he was blown to pieces for a start," James said, before he could stop himself. He forcibly stamped down on his bitterness; now was not the time or place for it. "The Sirius Black I thought I knew would never have killed all those innocent people, not even for revenge. Before he died, Peter said Black betrayed him and us to Voldemort. The idea is that Black led Voldemort to where Peter was hiding to get our location from him. And Voldemort was too strong for him."

"Everything makes sense," Harry said, hollowly. "What Malfoy said to me, remember? Of course he knew, his father was in Voldemort's inner circle." James did remember, he had not appreciated more evidence in the 'Sirius is a traitor' theory. "And you making me promise not to go after him. I couldn't understand why you'd think I'd go after someone who wanted to kill me, but it makes sense…"

"No," James interrupted. Absolutely not. "It still does not 'make sense' to go after someone who wants to murder you." He was on his feet. He didn't remember standing up.

"How can you say…" Anger had flared again, almost too much for Harry to speak. "It's all his fault! He's the one who…"

"You think I don't know that?" James said. His voice was rising too, and he couldn't stop it. "He's the reason you were raised by the Dursleys, why Lily and I missed ten years, and now he's trying to kill you. Of course, I want to go after him, but I can't. Neither of us can."

James crossed the room swiftly, gripping Harry by his shoulders. He dimly noticed that his hands shook, not with anger, but with fear. He couldn't lose Harry, not now. Not ever. Endangering his son was the true unforgivable sin. "Harry, promise me you won't go after him. He's dangerous, I know how dangerous he is. Promise me. Please," he added, unable to stop himself. Harry had willfully and purposefully gone after Voldemort twice already. With Harry at Hogwarts, there was very little James could do if his son decided to go after a mass murderer.

Looking slightly startled, Harry nodded. "I promise, Dad," he said. "I won't go after him."

James believed him.