It was eight years ago that Dr. Alex Beck (Francois Cluzet), a pediatrician, was spending a quiet romantic evening with his wife Margot (Marie-Josee Croze) at a lake where they had frolicked as children. One minute she was by his side on a float in the lake, and the next she was swimming to shore and going for a walk in the woods. Beck hears her scream, and that's the last thing he remembers. A lengthy police investigation concluded that Margot has been slain by a serial killer. But now two more bodies have been discovered in the area along with a key to a safe. A detective (Francois Berleand) has his eye on Beck as the chief suspect.

This complicated murder mystery has been brilliantly written and directed by Guillaume Canet based on a best-selling novel by Harlan Coben. The well-acted French film is populated by a handful of characters who all have secrets about that grim evening long ago. Beck finds himself pressured from all sides: the police are aggressively questioning him about matters he knows nothing about, three dangerous thugs are pursuing him, and he is shocked when he receives an email with a link to an video of someone who looks just like Margot with the message: "Tell no one. We're being watched."

Luckily, there are a few people that Beck can turn to for help: his lesbian best friend (Kristin Scott-Thomas), a capable lawyer (Nathalie Baye), and Bruno (Gilles Lelouche), the grateful father of one of his young patients who is willing to do anything for him. But others have information that is crucial to the case, and they aren't talking: Margot's father (Andre Dussollier); Beck's sister (Marina Hands), a skilled equestrian rider; and a wealthy man (Jean Rochefort) with a yen for revenge.

Tell No One is the kind of murder mystery that keeps you on the edge of your seat for its entire duration. It is a classy and sophisticated French drama.