Hadji Cheriff, a performer known for a variety of unusual abilities, demonstrates part of his act in the Thomas Edison studio. He has a large knife in his hand at the opening of the act. He then hurls the knife away and begins a rapid series of dance-like motions, executing numerous cartwheels and whirling movements.
Police Captain Kader Cherif knows the city like the back of his hand, and, as someone could say, never leaves his duty, because his apartment located on the first floor of the building opposite to the police station. He is assigned to investigate unusual murders in Lyon. Of course, he is using only legitimate methods which sometimes seem to be unusual and are displeasing his new partner Adeline Briard, police captain as well.