In April 2018, 9-year-old Nico is tormented by bullies who force him to steal an X-rated magazine from a 24-hour convenience store and tell him about a man who was shot and killed there 10 years earlier.

His mother reports her suspicions about the bullies having written the note to Nico's school principal which then results in further retaliation.

Then, 21 years later in 1976, members of the Basque separatist group ETA attempted to assassinate an Army general at the same location.

When David is declared brain dead with only a one-in-a-million chance of regaining consciousness, his family decides to pull the plug on April 12 much to Andrea's anguish.

After David's life support is disconnected, Jon runs to the maternity ward, shouting to the parents of a newborn their son must not go to the convenience store on his 10th birthday or else he will die.

Jon is subdued by hospital staff but escapes and returns to the convenience store, where he gets a call from Andrea that David has miraculously regained consciousness.

He writes down the warning Nico received earlier in the film and gives it to Héctor, the owner while wearing a video game T-shirt.

Jon then insists another customer is going to attempt a robbery which causes Héctor to call the police and ultimately pull out his gun.

Spanish director Daniel Calparsoro's thriller, The Warning (El Aviso), an adaptation of the novel by Paul Pen, is capably assembled but doesn't fulfill its own potential, betraying glimpses of a richer story than the one we actually get.

"[4] Jordi Costa of Spanish newspaper El País (Spain) compared the film to episodes of Lost criticized the storyline, writing, "Calparsoro puts his professionalism at the service of a story that does not create enough belief in the improbable so that the viewer is imbued with the mystery.

"[6] Joe Reid of Decider.com gave the film a more positive review, writing, "A well-acted and surprisingly affecting thriller, all things considered, and a satisfying mystery, if not a shocking one.