[2] The film stars Paul Kircher as Lucas, a gay teenager coping with the sudden and unexpected death of his father in an accident that may or may not have been suicide.

[3] The film's cast also includes Juliette Binoche as Lucas's mother Isabelle, Vincent Lacoste as his older brother Quentin, Adrien Casse as his boyfriend Oscar and Honoré himself as the father,[3] as well as Xavier Giannoli, Pascal Cervo, Wilfried Capet, Jean-Philippe Salerio, Erwan Kepoa Falé, Anne Kessler and Isabelle Thevenoux in supporting roles.

The brothers travel to Paris, where Lucas bonds with Quentin's good friend and roommate, the sensitive artist Lilio.

After spending quality time with Quentin at the Louvre, Lucas goes back to his apartment to discover Lilio meeting a client.

In the car on the way back to school, Lucas takes a vow of silence before punching a mirror and using the broken glass to slit his wrists.

He is visited by Isabelle and Quentin, begins jogging, listens to music, and continues privately struggling with his grief in church.

[6] Metacritic, which uses a weighted average, assigned the film a score of 64 out of 100, based on 5 critics, indicating "generally favorable" reviews.

"[9] Derek Smith of Slant Magazine noted that "where many films show grief merely as a crippling hindrance, Winter Boy sees it as an emotional state that constantly rises and recedes, disrupting the flow and morphing the meaning of everyday experience" and went on to praise Kircher, Binoche and Lacoste's performances.

On the latter two, Smith opined that "Binoche and Lacoste are superb in their small roles, and through their respective characters' attempts to both guide and restrain Lucas.