Mikä yö!: Colonel Barring has purchased the Maanala estate, where strange things are happening. She wants to cancel the sale and writes to Major Hector, who is acting as the owner's representative. The major sets off for the estate with the colonel, his wife, his nephew George, and George's fiancée Vappu. The colonel's son Leo also arrives, accompanied by his new love interest, Sirka. The group spends an unforgettable night in the haunted house.