The nightmare is the Mare of the Night, with its enormous nostrils and hooves. It resides in our consciousness, which is vulnerable when we are asleep, it is found in the melancholic darkness of instincts, in the passions and temptations that blind us, it is the echo of sorrow and nostalgia for time, which, while we prefer to remain stagnant, it runs, passes by, and leaves.

The nightmare is the horse, the disappearance of elements dominates this novel with amazons and breeders of purebred horses, and it unfolds in stables, horse training areas, racetracks, illegal horse races, and races organized for charitable purposes.

A new world that leaves Inspector Montalbano astonished and simultaneously deceived.