Brandon brings a girl home...and this doesn't sit well with Callie. Set after 3x10

It's prom and Brandon and Callie aren't going together, of course. They can't even be in a relationship. But that doesn't mean anything happening between them is out of the realm of possibility.

What happens when "Someone's Little Sister" plays Outlaws at All Ages Night with the Foster Kids in the audience? Brandon is with Lou, Callie is with Wyatt and all is well.. isn't it?