Un si grand soleil: Investigation into Stéphane Arnaud's death

The French television drama Un si grand soleil follows the investigation into the death of Stéphane Arnaud. After Stéphane is found unresponsive at his mas, an autopsy is ordered to determine if his death was an accident or a suspicious event involving head trauma or cervical fractures.

Investigators have discovered that Stéphane's car was found burned with his belongings inside. Additionally, traces of detergent at the mas suggest someone cleaned the scene to remove evidence. Yann has identified that Guillaume Sérignan purchased a plane ticket for Stéphane to travel to Buenos Aires, Argentina, a trip Stéphane had not mentioned to his partner, Alix.

While Alix suspects Sérignan of involvement, the investigation continues amid further complications, including the theft of a police badge and the disappearance of Stéphane's body from the morgue.