The breeze changes slightly in the air as Derek is looking up at the moon and taking in a deep breath, enjoying how relaxing the atmosphere is out here, especially by comparison to all the noise and excitement inside, when he catches a familiar scent. He pauses, but doesn't follow it, because while he and his cousin aren't that close, having the same conversation with her that he'd had with Scott is probably at the very bottom of his list of things he'd want to be doing tonight.

So when he finally looks over and she actually waves and greets him, Derek assumes that it's because she recognizes him. Or, worst case, she at least knows that he's a werewolf; she can smell that on him, almost definitely.

"Hey," he replies, his eyebrows lifted slightly with uncertainty. "...Malia?" he asks, just to be sure. Because with people here being from different worlds, for all Derek knows, she's just some girl who looks exactly like Malia but...isn't. He'd rather know before the conversation continues and he makes himself sound like a complete nutjob or creep or something if she's not who he thinks she is.

She smells like Malia...but it's better to be safe than sorry.