Seventeen-year-old Zeina is placed in a foster home with a family in Värmland. Bror, the family's son, is the same age as Zeina. He is anything but happy about having gained a sister.
Zeina and Bror are grounded, but Zeina runs away. Soon, she is at a party with the local epa-raggers. Things get out of hand, and Bror has to come to her rescue.
Zeina convinces Bror to go to a concert. She realizes that the village priest is behind it in an attempt to attract young people to the church. Everything ends in chaos when a newfound friend lights a joint and the fire alarm goes off.
While the adults swirl around to the local dance band, the village's young people gather on the hill behind the dance floor. Here, Zeina realizes that Bror needs a lesson in kissing.
Bror has signed up for the local race for epa tractors. Zeina realizes it can only end in humiliation. To help Bror win, she decides to put an end to Bror's worst competitor.
The town's richest and most self-absorbed girl, Ebba, throws a party. She has plans for the evening that involve Bror. Soon, they are alone in her room.
The family suddenly gets bigger when Ebba, Zeina's worst enemy at school, moves in. As if living under the same roof weren't enough, Ebba has also hooked up with Bror.
Social services suddenly show up at the Mårtensson family's house to see how Zeina is doing. They don't think the family seems suitable and want to take Zeina away. When no one notices, Zeina runs away.