A classic tale of a brutal murder of a wealthy gentleman, whose disfigured body is found on the railroad tracks. The originality of what seems like a banal investigation is that it is carried out by an amateur—a young clerk, Antonin Bonassu, who lived on the same stair landing as the famous private detective Paddy Velgon.
Taking it upon himself, during the detective’s absence, to receive all visitors who came to him, he once couldn’t resist the temptation to “play detective a bit” and started investigating the case mentioned above—leading to completely unpredictable consequences.