Two murders. A missing child. And a killer searching for the treasure of the Knights Templar.

As a native English speaker, Luka Williamson isn’t expecting much from La Ciudad del Ingles. He has volunteered to spend one week talking with Spaniards who want to improve their English, in exchange for a free vacation at a luxury resort in the countryside.

The program begins with a tour of La Alberca, a nearby UNESCO heritage town where a sacred pig roams the streets and the shops sell loins of jamón for tourists to take home. But the local history lesson quickly takes a back seat when a postal worker is found murdered in an alleyway near the town’s main church.

The language program participants are told to ignore the crime. The only witness: a local girl with a mysterious background. She tries to tell Luka what she has seen, begging him to team up with her to find the killer.

While tracking the strange nocturnal activities in the resort villas, Luka realizes that anyone in the program – including the organizers – could be a suspect or the next victim. His suspicions are deepened by the shocking announcement of another killing. The only clue: a skull inscribed with the loyalty vow of the Knights Templar.

Ancient oaths collide with modern conspiracies as the killer makes another bold move. Luka must solve the mystery to find his way home.