Luise, a mischievous girl, is spending her summer vacation at a summer camp. As usual, she's playing pranks with her friends when she meets Laura, a new friend who looks exactly like her but has a completely opposite personality. Initially, both are surprised by their similarities, and while talking, they discover they are twin sisters separated in childhood. Luise lives with her father. Laura lives with her mother. The two devise a plan, using their resemblances, to swap places: Luise pretends to be Laura, and Laura pretends to be Luise, and they go to visit their respective parents. After reuniting with the father and mother they had missed since childhood, the two exchange letters and plan to live together again as a whole family. Meanwhile, Laura learns that her father is going to remarry, and her mother realizes that Luise is impersonating Laura. This incident leads to the separated parents reuniting and, at the request of their twin daughters, marrying again, making the two sisters happy.