The popular Danish family are vacationing on the island of Bornholm. Unfortunately, they have not been able to get hotel rooms, but Tiny Per, always resourceful, have come up with the idea that they must sleep in a tent. Father and Uncle Anders are not quite enthusiastic about the idea, but there is nothing else to do.
At home in the small family is nothing new. Tiny Per is the school's mischief maker, Sister has heartaches, Mie and Ole has to be in the school play, etc. But suddenly something happens. Good old Uncle Anders has a twin brother in the United States. He called Sofus, and now he comes home to celebrate 70th birthday. He was a troublemaker when he left and now he has become even worse