The film takes place over the course of a single night: the longest night of the year, between December 21 and 22 (the winter solstice), when the sun sets around 4:30 p.m. and rises the next day at 7:30 a.m. A long night in which the stories, destinies, anxieties, and dramas of a provincial town in the south (Potenza) intertwine, even if only briefly. Fifteen hours of uninterrupted darkness in which human destiny becomes exceptional, as the night causes the anchors of the day to be lost and four personal stories suddenly accelerate.

Three well-off young men—former students at Rome’s prestigious all-boys Catholic high school San Leone Magno—brutally tortured, raped, and murdered two young women in 1975. The event, which came to be known as the Circeo massacre, shocked and captivated the country, exposing the violence and dark underbelly of the upper middle class at a moment when the traditional structures of family and religion were seen as under threat.

Tangled up with blackmail and crooked cops, the son of a former gangster seeks out his father's old friends, who risk everything to save him.

To rescue his daughter, an unstable Special Forces veteran unleashes his inner beast as he pursues her kidnappers — and soon becomes a suspect himself.

In the past few days Rome has been the scene of a singular event: when it rains, the manholes exhale a dense steam whose origin and composition is unknown. No one can imagine that whoever breathes in the mysterious substance will have to deal with what he/she represses, their darkest instincts, their anger. Not even the Morel family.