Four children—Kerttu, Liisbet, Oliver and Kaspar—find a mysterious diary in the attic. The diary
reveals that its owner, Saara the Girl Witch, is trapped in the spirit world
and begging for help. In order to free Saara, the children have to solve a
series of difficult and dangerous tasks.
Despite the ingenuity and courage of the helpers, the whole undertaking hangs on
the verge of failure.