Veiled Rivalries

Peyton chimed in, "She probably only got that dress because Vaughn and Valerie used to be classmates, so she asked Vaughn to borrow it from Audrey for her."

That would explain why Sloane looked so uncomfortable earlier when she was trying to say she wasn't involved with Vaughn.

And Vaughn looked pretty irritated when he was talking to Harper earlier.

Turns out, Sloane was just using Valerie and Va