Frank loves Charles, but they're both men. And Frank is just a mechanic while Charles is the boss's son.
When Charles's parents throw a ball to find their only son a wife--whether he wants one or not--Frank dons a frock at the urging of his roommate to attend. One time, one dance in the arms of the man he loves, one memory to cherish forever. He doesn't count on Charles's choosing Frances, his female alter-ego, for a bride. Knowing it can never be, he confesses to not being a woman, and flees.
He doesn't expect Charles to connect Frank to Frances. He doesn't expect Charles to prefer--and pursue--Frank. But the obstacles between them are real, regardless of what either man wants.