Dr. Otto Dernberg is in town for an important meeting when he falls smitten with the fabulous Carlotta Ramirez. While in town Otto visits his kid brother, Ralf, who is best friends with Charley. Ralf and Charley are planning a party. Unfortunately for the boys, Charley's aunt, whom he has never met, wants to visit with him on the same night. When everyone cancels including Charley's aunt, the girls want to leave. Big brother, Otto hears the girls and in trying to help his kid brother out makes an emergency phone call to his butler who happens to be dating Carlotta's secretary. Otto shows up at the party dressed as Charley's aunt, calming the girls and they agree to stay. Charley's real aunt changes her mind about visiting her nephew and shows up only to see someone dressed in her dress! She secretly figures out that it is Otto.