Real v Fake

Intro
The "Real v Fake" plot is when there is an impostor trying to pass as another character for their own gain. Typically, The Audience already knows that the impostor is a fake.

Plot Sample
Guy owns a very expensive diamond in his house that is guarded by his friend Ava. Hugo knows this and wants to steal the diamond. But for him to get inside Guy's house, he must prove he is Guy trying to get into his own home to Ava. So Hugo creates a Terrible Disguise that looks like Guy, goes over to Guy's house in his disguise, and meets Ava who is outside Guy's house. Ava is about to welcome "Guy" into his home unaware that it's actually Hugo in a Guy costume, but then the real Guy shows up and sees the impostor Hugo. Ava tries to figure out who the real Guy is by asking the two a question Only The Real One Can Answer. Of course, the real Guy answers with ease, exposing Hugo as the fake.