С 1, с 6: Ana and Lucía go missing in Monteperdido after they leave school. Five years later, one of the girls reappears; she has been in a car crash. She is unconscious and the driver is dead. The news will turn the lives of the affected families upside down. UCO agents Lieutenant Santiago Baín and Sergeant Sara Campos arrive in town to take charge of the case. The investigation turns out to be a race against the clock. With the help of Corporal Víctor Gamero, they will have to solve two fundamental questions: who is the deceased man found in the car and where is the other girl who went missing five years ago?