Half-senile Ossi and his wife travel to celebrate Ossi's 75th birthday at an old people's home where most of their friends are already staying. Just before the festivities Ossi suddenly disappears and goes on tour to 'make an inventory of his life'. He checks into a hotel, poses as a publishing director to lure an aspiring female novelist, next travels to bother his old mistress and her new husband with his surprise visit and obnoxious comments, then goes to see his son for the first time in 34 years just to receive an even colder treatment. Meanwhile, his equally demented wife goes looking for him with a local policeman.

Adult Camp is a comedy about the bumpy road to personal growth. A group of men and women, strangers to each other, choose to spend a different kind of summer holiday week by traveling to the beautiful Turku archipelago to participate in an inviting, upgraded version of an adult camp. When they discover that the galloping horses from the camp's sales video are just symbols of a free mind, and the guru of the camp takes off to witness his dog in labour, the participants are forced to examine themselves and each other to find the necessary elements for growth. Perhaps the camp doesn't fulfill its promise of the "most wonderful week of your life", but one thing's for sure - no one returns home the same.