Henkka Virtanen finds evidence of a possible crime on his way to school. With his friend J.K. Kivimutka, the boys decide to investigate what has happened, because these criminal cases are the responsibility of the detective agency they have set up. When it turns out that mailboxes in the area have disappeared during the night, the detective bureau has already two crimes to solve. A fun and exciting adventure begins, in which the boys also have to face their own fears.
Mikael Ehn
as Henkka Virtanen
Veetu Hietanen
as J.K. Kivimutka
Anna Pitkämäki
as Henkka's mother
Tapani Kalliomäki
as Henkka's father
Annu Valonen
as Teacher
Pirjo Heikkilä
as J.K.'s mother
Sira Junno
as Sister Kaarina
Verneri Tinkanen
as Kauko Mäyhkö
Heikki Nousiainen
as Old gentleman
Kaija Kiiski
as Old lady
Santeri Töyry
as Moped boy #1
Anton Riihilahti
as Moped boy #2
