Ciudadela, Menorca. When María Médem returns to her job as an officer in the local police after maternity leave, two sexagenarians are murdered on the island. The house where their bodies are discovered has three notable features: a strong smell of mint, the same song by Raphael playing continuously on the computer and absolute order in all the rooms. As a former member of the Barcelona Homicide Squad, María is asked to take charge of the complex investigation. Neither reconciling her responsibilities as a mother with her work, despite the occasional absences of her husband due to his job, nor even the disturbing presence of the enigmatic Rioberto Rial, head of the Madrid Homicide Unit, are any way near María's main concerns.