Anita works at the switchboard of a small taxi cooperative. On December 24(th), Anita and her colleague Gea (a very positive girl, a tropical fish lover, who breeds fishes in an aquarium at the company, and mother of a small child) are at the switchboard. Tristano, Anita's husband, works as a taxi driver with the BLU38 code in the same company. Andrea, the only son of Tristan and Anita, was an eighteen year old singer and poet, intelligent, sensitive, insecure, with a fragile soul, addicted to heroin with an infatuation with his mother. He killed himself on Christmas Eve the previous year, right in the bathroom of the taxi cooperative, where Andrea barricaded himself to perform his extreme gesture. Everything happened live on video in front of the mother's eyes, as Andrea often does; in fact we hear audio and see short recorded videos of Andrea - often in the company of his girlfriend Anna - in which he declares his love to his mother. Exactly one year after her son's suicide, on Christmas Eve, Anita discovers that Tristano is implicated in the death of a minor - who will be discovered being Anna, a little girl with the aptitude for playing extreme games - through a round of phone calls, revelations, intuitions and events, while she is on shift at the switchboard. Anna was drawn to a meeting of devotees to the Shibari Japanese practice and accidentally dies during a "game". Tristano is the gray eminence who organized this type of meetings, assisted by a certain Matilde, also very young: this will be discovered only at the end. Panicked after the accident, Tristano and Matilde begin a useless and irrational escape aboard the Tristano's taxi during which Tristano keeps in telephone contact with his wife Anita, to whom, however, he does not tell the truth. Nevertheless, Anita reconstructs the facts patiently and with great fortitude, also helped by a phone call to the switchboard from a police inspector, who, in the meantime, discovered and recognized Anna's body. The phone calls between Anita and Tristano are becoming more and more fragmentary, often the communication is interrupted or the phone does not answer; and when the communication takes place, it is more the voices in the background of Tristano and Matilde, who now accomplices now enemies, that weave the threads of the plot and reveal flashes of truth. Meanwhile Gea, who has always tried to comfort Anita, must leave the switchboard and go back to her baby. Anita thus remains the only active operator on Christmas Eve.
Tristano is also left alone, after a brief quarrel with Matilde, who now accuses him of being solely responsible for Anna's death. He decides to tell Anita everything. His wife had already guessed it, and despite having a fit of anger and feeling pity for the girl, she has to face the psychological recovery of her desperate husband, who wants to jump off an overpass of the ring road rather than to undergo a shameful trial.