December 2013, San SebastiÔan. A dentist appears dead with a syringe stuck in his forehead and his body covered with bills. The murderer has left a hidden message written with the victim's blood. Max Medina, concerned about the proximity of the birth of his first child, must face this case alone, as his partner Erika Lopez is under psychological treatment to overcome the dramatic events of last year, and the agent of the scientist Joshua O'Neill he is sick. Only Virginia, a mischievous and insolent young woman, but an expert in computer science, will help Max in his investigations. A month later, coinciding with the start of the Year of the Horse, the appearance of new victims and messages will lead Max and Erika to start a race against the clock to stop the perpetrator of the crimes, while the mother of all the storms looms over the city, foreshadowing the disastrous events that are to come.