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. 　　译文(2): Henkka Virtanen 在去学校的路上发现了可能的犯罪证据。和他的朋友 J.K. Kivimutka 一起，男孩们决定调查发生了什么，因为这些刑事案件是他们设立的侦探机构的责任。当发现该地区的邮箱在夜间消失时，侦探局已经有两起案件要破了。一个有趣和令人兴奋的冒险开始了，其中的男孩也必须面对自己的恐惧。