BahÃa Blanca is a mystery thriller that follows the investigation of the murder of Pocho Martin, whose body was found dead on the shore of a fishing village. The Commissioner Carlos takes charge of the case and works alongside forensic Ramiro to identify the killer. Along the way, they encounter various characters that lead them closer to the truth, including Silvia, Pocho's friend, and Crackpot Oscar, who warns them about the dangerous sirens of Deer Island.
As they follow the leads, they come across the sisters Lila and Mary, who run a tavern/brothel near the beach. Carlos and Lila share a history, which adds to the already complicated situation. Lila is a potential suspect, but the evidence doesn't point to her directly. Throughout the investigation, they find themselves at odds with the local fishermen, who seem to be covering up something.
Silvia is more concerned about her impending wedding with Andy, and the news of Pocho's death throws her off balance. As Carlos and Ramiro delve deeper into the case, they unravel a complex web of deceit and betrayal that leads to the resolution of the murder mystery. The film is set against the backdrop of a quaint fishing village, where everyone knows everyone's business, and secrets aren't easy to keep. The suspenseful plot, coupled with stunning cinematography, makes for a riveting thriller that keeps the audience on the edge of their seats until the very end.