Candela, an unconventional judge with character, is sent to the remotest possible posting, El Hierro, an island that is full of peculiar characteristics, where she doesn’t quite fit in. As soon as she arrives, she must face a murder case. The victim is Fran, a young man who was going to get married on that very day. Everything seems to suggest the culprit is Díaz, Fran’s boss and father of the bride, a shady local businessman who had served sentence for murder as a young man.

Candela must decide if Díaz is kept in pretrial custody. Against the criterium of her team, and of the whole island, he is released on bail, although he won’t be allowed to leave the island and he will be closely monitored. In any case, it’s an extremely unpopular decision, compounded by Díaz’s determination to find the real culprit by himself. Candela, at odds with her own team, needs someone by her side to rely on, someone who also knows the ropes of the island. She takes a new controversial decision – she includes Reyes, a local police officer, in the investigation team.

The investigation brings to light the dark side of Fran’s life: he had established contact with some mysterious person in Holland, and he had an affair with an unknown lover. Did Fran die because he was involved in some shady business? Or was it a crime of passion? Both Candela and Díaz make progress in their respective investigations, carried out independently. Díaz believes Fran used his contacts from the milieu of a dangerous drug smuggler. And Candela makes an uncomfortable discovery – Fran’s mysterious lover is someone very close to her.

During a clandestine trip out of the island, Díaz discovers that Fran, just before he died, was trying to sell some valuable merchandise. He doesn’t know what kind of merchandise. And above all, he doesn’t know who was the partner from El Hierro who cooperated with him in the operation. This mysterious partner could be the murderer, because he is trying to get something from Fran’s environment (he broke into his and his mother’s houses…) Meanwhile, Candela feels the police investigation is progressing too slowly. The only person she trusts is Reyes. And in fact, the local police officer does discover (and us with her) who the murderer is. But she won’t live to tell the tale.

The murderer, upon being found out, kills Reyes. From that moment on, he faces the difficulty of getting rid of the body in an island like El Hierro, where it is difficult to vanish without trace. Especially after the disappearance of the local police officer gives rise to a public outcry. There is a reaction in the island. Police forces, civil defense services and volunteers start a desperate search. The most likely scenario is that the murderer Reyes was investigating is back in action. Candela is devastated; she feels guilty because she is the one who enlisted Reyes for an investigation that strictly speaking was not part of her work duties.

Reyes hasn’t been found, but the search operation leads to tracing down a sunk boat which will provide new clues. The boat was used for smuggling African diamonds, and was found by Fran in a diving excursion. Diamonds are the shady business he was involved in. Candela cannot accept defeat in the search for Reyes, or the slowing down in the speed of the investigation as a result of the Descent, a religious festivity that paralyzes the island every four years. Desperate, she tries to get Díaz’s cooperation, who is also vent on finding the real culprit. The murderer feels the investigation is closing down on him. He considers fleeing, but he hasn’t found the diamonds hidden by Fran yet. And he diverts attention to everyone’s ideal false culprit – Díaz.

Díaz avoids being arrested by desperately fleeing. But leaving the island without being found out is impossible, especially with a police operation that shut up firmly the few available exit routes from the island. Finally, Díaz gets caught. And the island sighs, relieved – they will be able to celebrate their Descent in peace. Only three people in the island seem anxious: Díaz himself, who knows that someone has planted false evidence to frame him; Candela, who has a hunch there must be something wrong; and the murderer, who got the police off his back, but who continues looking for the diamonds that are at the root of his whole adventure. In the middle of the Descent festivities, the murderer discovers the location of the diamonds.

The murderer, taking advantage of the chaotic situation during the Descent, manages to get hold of the diamonds. But now he must face a new obstacle – the drug smuggler whose help Fran had enlisted has been following him, and he wants to take the diamonds himself. Meanwhile, Candela and Díaz go over their investigations together, and find the key to identify the murderer. They trace him down when he is on his way out of the island. They have caught him. But he is not prepared to surrender.