The Shroud tells the gang that there are some supernatural beings, the Undead, who seek to hunt them down. Costa discovers the tunnel the boys found, which makes him suspect that someone from the town is a possible captor.

The boys are left without allies so Javi decides to look for the Undead at the town fair and follow them to his sister. Olivia discovers her grandmother's red notebook and begins to feel a supernatural gift awaken in her.

Javi and the gang chase a ghost to try to find out where the girls are being held. Javi manages to convey information to his father, but the Undead come forward with a masterful move.

The Undead deceive everyone by making a false revelation. The boys make a great discovery at the Aigües de Busot Spa. Costa discovers that the cases of three missing minors happen every three years in Levante.

Costa, Mario and Roca, Bea's father, receive very important information that guides them to the Spa. There everyone will discover something that can change their destinies forever.

Anabel, a ghost friend of the Shroud, joins the gang; Olivia convinces Costa to reopen the investigation into a new ritual.

The gang realises that the Undead intend to separate them to catch Javi; Costa, after forcing a police search at the hotel without obtaining results, is questioned by his and Mario's father.

The gang has to come to the rescue of Javi at the hotel, after a fight between Evelyn and the Marquis; the lives of Sandra, Olivia and Bea hang in the balance.

Javi starts a race against time in which he has to gain allies and work on avoiding old enemies along the way.

With Javi and Zeta trapped, Bea and Olivia must take the lead on a rescue mission with an uncertain end.