It's the day of Momo's first piano recital. As she nervously waits for her turn to play, she tells herself, "I'll be okay ... I'll be okay ..." Then she hears a voice nearby, also saying, "I'll be okay ... I'll be okay ..." It's a mouseling! And the little mouse is nervous about her first performance, too. The mouseling invites Momo through a small door backstage, where Momo is amazed to find a miniature theater filled with an audience of finely dressed...