One autumn day, Ivar goes to the Botanical Garden in Oslo to visit Maria who is the mother of a little girl named Tilla. Ivar is a child psychologist and had Tilla observed a few months earlier. Treatment for her was agreed upon, but Maria has not returned with Tilla. Now Ivar finds her sleeping under a tree in the garden, and he meets Maria bent over a microscope in the laboratory. Maria has become even more nervous and unbalanced than the last time he met her, because nothing has been "corrected" as quickly as she had hoped -- Tilla has not spoken now for a year and a half. Maria herself is on her way to being as closed off as her own little girl. Ivar persuades Maria to come to the pediatric psychiatric clinic with Tilla so they can begin her treatment. There she meets Mimi Backer. But neither does Mimi get Maria to open up about her experiences with Tilla. In the clinic's observation room, however, the first little flicker of light falls on the mystery...