Billie is strong for Fred, but she catches him flirting with a chum and resolves to administer drastic treatment. The next time her lover calls he is informed that Miss Billie is entertaining a caller and is compelled to wait on the porch. A dapper young man eventually leaves the house and Fred makes a second attempt to get in. He is informed that Miss Billie is expecting a foreign gentleman, who arrives shortly and stays much too long. When he departs there is a suspicious powder mark on his shoulder. The strangers have both seen Billie, garbed in her brother's clothes. When Fred is admitted, remorseful, penitent and jealous, Billie keeps him waiting while she dons her dress. The plot is revealed by a trouser leg which protrudes beneath her skirt, but Fred admits that Billie "put one over."