Max is a Jack Russell dog genetically modified for criminal purposes so he is able to talk. Running away from the criminals he's working for, he is wounded, then saved by detective-wannabe Alberto, who is fire and house-hunting. They end up staying with Alberto's sister-in-law Marta and her two children. Thanks to them all, Alberto finally manages to be a detective, and he and Max establish their detective agency: Sabuesos.

Nadia and Adrián starts their particular world war when she files to divorce him.