The Olsson family is tired of sitting in the apartment in town and decides on a white Christmas in the country. In the newspaper they find an advertisement
Lillan gets a voltmeter from a classmate and discovers that it's haunting. After an unsuccessful attempt to be intimidated, the ghosts Jean and Staffan decide to take on the hard gloves.
Leif and Astrid have realized that it's haunting Greveholm and are terrified. They want to go home but the children refuse. Can Melitta, Ivar and Lillan convince the parents that the ghosts are not dangerous before Christmas Eve?