Christian is six and very fond of his baby-sitter, Josephine. His mother prefers the older, more reliable Mrs Bruus. Christian has to hatch a cunning plan to get Josephine instead of Mrs Bruus. The plan misfires, and he suddenly finds himself at home alone with his two-year-old sister, Louise. Christian steps outside for a moment, but the front door slams in his face. He is locked out and Louise locked in.