For a long time, Pröfy has been looking to build a house. For the day that it will be done, Waha will be able to live with him, they will live happily and will have many small trollilons. Alas, the architectural failures of Pröfy accumulate until they depress him completely. Without a house, more Waha, more future. The half troll dark in the neurasthenia, until it becomes immobile and insensitive to everything. A troll cannot be ill: it is therefore the human half of Pröfy that must be treated. The human head doctor who is consulted, after having installed Pröfy on his couch, suspects a strong identity crisis: Pröfy needs to know more about his origins. So these are our friends launched in a quest for the father on the surprising mode of troll psychoanalysis...