The feast day of the Holy Innocents is as good a day to die as any other. This must have been what Gervasio Álvarez thought when he heard the news of the appearance of a body. Andrea Mérida, the widow of a soldier, mother of three children, a pensioner, has died from a cocaine overdose. No one heard or saw anything. No one can explain if the drug was taken voluntarily, by accident or intentionally. No one seems to gain a thing from this death. Christmas becomes tinged with despondency. And this is why Álvarez decides to bring a good friend of his out of voluntary retirement. 'Blue Christmas' marks the return of a more human, more fragile, more profound Ricardo Blanco. An intense, melancholy story, characters and time which reflect, like few others, the story of a crisis. The sixth instalment of the saga of the Canary Island detective is perhaps the most socially conscious and intimate of them all.