There's a costume party where Duckburg's millionaires will disguise as superheroes. When Fethry finds Uncle Scrooge will disguise as the Red Bat, he asks advice to Donald as the Red Bat has too many enemies who may believe him the real deal. Donald suggests the actual Red Bat should protect Scrooge.
The Red Bat sneaks into the party and finds someone disguised as the Red Bat so he warns him of the danger, but he turns not to be Scrooge but John D. Rockerduck instead. Rockerduck is angry to have the same disguise as Scrooge so goes to rent a new one. The conversation is overheard by Dangerous Dan and Idgit the Midget, who had infiltrated into the party and plan to ambush a Red Bat as they are Duckburg's richer men.
The Red Bat finds Scrooge and convinces him to rent a different disguise than the Red Bat one due to the danger, but then Scrooge signals the Red Bat is the one in danger now. Realizing this, the Red Bat escapes the party but is ambushed by the villains who believe he may be Scrooge or Rockerduck. There's a fight and all three get knocked out.
Scrooge and Rockerduck arrive and find the unconscious fighters, then Scrooge unmasks Idgit while Dan awakes, unmasks himself and turns himself in, with Scrooge noticing he shaved his mustache. Rockerduck gets curious and also unmasks the Red Bat as Fethry, but luckily Donald arrives with an alibi story, about Fethry just taking the same disguise as Scrooge to enter the party.