Dez, Trish and Austin convince Ally to attend the annual Zaliens Convention in Miami. Unfortunately, Trish and Dez stumble upon real Zaliens and the foursome are forced to devise a survival plan.

Carrie threatens to tell her sister Piper, who is going to the prom with Austin, that he would rather attend the event with Ally. Meanwhile, Piper grows suspicious of Austin's relationship with Ally.