"I've not lost it, it was stolen," Sirius insists because there's a very distinct difference.

And it's, by far, not the worst thing he's without right now, but it's a much easier thing to focus on than his missing godson. Sirius shoves Kell's jacket it into Kell's hand before taking him by the wrist and, without another word, Apparating them both into a little room nearly identical to the one they'd just been in, though with notably fewer bits and bobs and not a single map in sight.

"And you can help me look for Harry," he continues, ignoring the voice in the back of his head, the one shouting that Kieren's right after all. That he reason Sirius hasn't yet found him is not because he's lost or stuck in this other place, but that he's truly gone. He stops short of the door, turning to look back at Kell. "Do you have your own magic for that?" he asks with a blossom of hope. "For finding people."