The summer holidays are starting! This year, however, Flo doesn't want to be separated from her beloved dog Lassie. Instead of spending their holidays in Gran Canaria with their parents, the boy and his furry companion go on a trip to Aunt Flo's farm with family friend Gerhard. The woman lives there with her children and her Jack Russell Terrier dog. When Flo and her new friends learn about dogs disappearing in the village, they decide to investigate. The real worry comes when they lose sight of Lassie and their aunt's beloved dog. It turns out that someone broke into the house and kidnapped a small dog! The three friends, together with the luckily found Lassie, set out to find the thieves and rescue the little dog.