A cold December night. After a series of peculiar encounters, two little girls cling to the last remaining glimpses of Christmas magic.
Detective Surprenant, a veteran of major crimes in Montreal who took refuge in the Magdalen Islands, investigates the murder of a teenage girl with the help of his colleague Geneviève Savoie and inexperienced police officers, even giving up his vacation to resolve this sad story. However, he must deal with the arrogant chief inspector Sébastien Gingras, dispatched from Quebec City and with whom he has disagreements.
When Maria thinks she's at the bottom of the barrel, she discovers that this barrel has a double bottom: no job, no money, no worthy accomplishment and now a dying mother begging her to do something with her life. before his death! She has no other choice but to get back in hand and find a career ... But what can she do with a 7-year-old BAC in communication and no work experience? Believe it or not, she can become a substitute in a high school! Thus, Maria, 30, as responsible and stable as a 14-year-old teenager, returns to high school in the role of the one to whom she threw pieces of erasers: the replacement. Too jaded teachers, rebellious teenagers, intimidated or not sufficiently denounced, she will be confronted with the reality of teachers and young people today and, who knows, may discover a vocation.