L'assassino della porta accanto

A man is killed with a shotgun blast in an apartment building. Upon Nick Raider's arrival, the interrogation of the condominiums begins, with the collaboration of a couple of policemen on patrol, but someone doesn't open the door to one of the officers who knocks on the door: he prefers to shoot. The policeman is seriously injured and Nick breaks into the apartment, but finds only a frightened child. The claustrophobic walls of the building and the condominium microcosm hide more than one secret to bring to light...