Waking up naked in a strange place can be unnerving in and of itself, but when the person waking up finds himself lying inexplicably next to a lamppost in the middle of a forest, it's a safe bet that things can only go downhill from there. When the person in question is Sirius Black, the downward spiral becomes a solid guarantee.
The first step occurs when Sirius realizes that he isn't alone. He squints at the young man lying nude on the ground next to him: a bit on the young side but quite attractive, even with the old-fashioned pageboy haircut, and he smells like …
Remus, Sirius' mind whispers, and then it all comes back to him in a flash: the Department of Mysteries, Bellatrix, Harry … Harry. He scrambles to his feet, looking around frantically. Where is his wand? Where the hell is he? Panic begins to set in as he realizes he has no fucking idea what's happening.
Then comes the next step in the plummet toward rock bottom: the biggest lion Sirius has ever seen is standing not three feet away from him, its great golden eyes fixed on him. When Sirius realizes that try as he might, he can't change into Padfoot, that's the proverbial straw on the camel's back. If the universe has got it in the plan to play a giant cosmic joke on Sirius Black, then what can he do but give up and play along?
So Sirius begins to laugh. It starts as a nervous giggle, at the instant in which he realizes he can see completely through the lion to the trees on the other side. It turns into a chuckle when his companion wakes and sits up, blinking. When the other young man jumps to his feet and throws his arms around its transparent neck - that's when Sirius loses it completely. He falls to the ground, clutching his sides as he roars with hysteria.
The stranger watches him with wide eyes. "Aslan," he says to the lion. "What's wrong with him?"
When the lion answers softly, Sirius stops laughing. Its voice is rich and musical, like trumpets in the distance; he can't help but listen.
"Be kind to him," the lion says to the young man. "He has made a great sacrifice, but he very nearly lost his way."
Sirius sits up on his knees, leaning back on his heels and looks at the lion very carefully. It's more solid now, less transparent. As he watches, he can see more details coming into focus: long golden eyelashes, the twitching ripple of muscle under fur, stiff whiskers tugged at by a gentle breeze. The lion is actually quite fascinating. He has to resist the urge to get up, go over and run his hands through the silky mane.
Then the lion smiles at him. "Be at peace, Son of Adam. Long has your heart been heavy, but now you are free of your old burdens." The lion butted the young man with his head. "I cannot stay; in three days' time I shall return to you. Until then, fare well, King of Narnia. Bring this man to your home and look after him for me."
The stranger bows. "As you wish, so shall it be."
"What is your name, sir?" the stranger asks Sirius, after the lion has vanished.
Sirius stands up, self-conscious again of his nudity. The stranger does not seem at all ill-at-ease over their mutual state of undress, so he shakes it off and pretends this kind of thing happens to him every day. "Sirius Black. And you?"
The stranger bows politely, pressing a hand to his smooth, lightly muscled chest. "Caspian, King of Narnia, Sovereign of the Lone Islands."
"King," Sirius says wonderingly. "How does a werewolf get to be King?"
Caspian pales. His hand strays to his hip for a moment, where Sirius supposes he might have carried a wand or a sword or something if he were wearing any clothes. "H-how did you know -"
"I can, er, smell it," Sirius says quickly. Caspian's eyes widen, but Sirius holds up a hand. "I'm not a werewolf. But my - my best friend is. Was. Is. Well, wherever he is, he's one. I'm an Animagus, although my powers don't seem to be working at the moment." He tries once more to shift into Padfoot - and is caught off guard when it actually works.
Caspian looks at the black dog with increased interest. "What an amazing power you have," he says. "I cannot control my change. I must come out to the forest at the full moon, as I did last night."
Sirius transforms back, a little sheepishly. "Well," he says, "It's working now. Something must have been blocking me before."
Caspian smiles. "Well met, Sirius Black, Animagus. Welcome to Narnia."