There are two weeks to go before the wedding of Lieutenant Valentina Redondo and Oliver Gordon. In the midst of preparations, however, news reaches them of a massive attack on the Temple of Water at the famous Cantabrian resort of Puente Viesgo.
At the time, a group of businessmen were staying at the facilities of the idyllic water paradise and everything indicates that a highly dangerous chemical weapon has been used to commit the massacre. Valentina will have to cooperate with the army and a special UCO task force to solve the crime.
They soon discover that a cruel and skillful mastermind has set in motion an implacable strategy, executing each of his moves with extraordinary coldness in a clear challenge to the intelligence and deductive skills of Valentina and the very reader. Lieutenant Redondo will come to doubt what actions she should take, because suspicions will soon be aimed at someone she has never seen but who, deep down, she feels she knows. Danger is a racing pulse that never dies down.