At Bi-mon-sci-fi-con

Phineas (dressed as batman) and Ferb (dressed as Robin) go with their sister Candace (that is wearing her tipical clothes) at the Bi-mon-sci-fi-con (BI-MONth-SCIence-FIction-CONvection), where they try to seld a comic book with their adventures. Candace discovers there that Jeremy is a big fan of comics and tries to get dress as one superhero. Meanwhile Doofenshmirtz is dressed as Darth Vader in a Star Wars´s fans convection trying to built his own "Death Star-Inator"