Hard-working Kusti and Iti eagerly pick strawberries at the edge of the meadow. As dusk falls, the children begin to feel tired and fall asleep at the foot of a large rock. During the night, Kusti is awakened by creaking laughter and shaking. An evil witch who lives in the forest has found the children and lures them to follow her through the dark and scary forest. When they reach their destination, the children realize they have arrived at the witch's ramshackle cottage. Two buck-toothed trolls also live there, who are always hungry and fight with each other over the slightest things.

The witch orders Kusti to take care of the animals and Iti to look after the troll family's unruly child. The work is extremely hard, and they decide to run away. However, Iti does not want to leave the little troll boy in the forest with the nasty trolls. The three of them run away back to Kusti and Iti's family home. How will the human family and the troll boy get along?