Franco is a minor officer who is unexpectedly confronted by Lorenzo, a half-brother with a high IQ. Lorenzo helps him investigate an apparent suicide case in which there is something more.

Franco is overwhelmed in his first job with the homicide squad. Lorenzo suggests investigating the dead man since no one claimed his body.

The producer of a quiz show is murdered. Franco takes advantage of Lorenzo's erudition to enter the channel incognito.

At a camp, Lorenzo learns about the legend of the lonely stranger. Lorenzo is excited and suggests that his companions investigate what happened.

A businessman dies. His wife's behavior is strange. Lorenzo invents a microphone and they manage to listen to conversations, which helps them connect the dots.

A sniper kills three victims in different places. In the middle of the investigation, an inspector appears to assess how Lorenzo lived. Mansilla "hires" Marcelita to pretend to be Franco's girlfriend, thus covering up the mother's presence in the home.

The Montero brothers went to see a play. During the play, the main character is murdered and the culprit appears to be one of his fellow actors.