To discover in oneself incredible powers and abilities, to decide on risky deeds, which I could not even imagine before. Perhaps this is possible only in an extreme situation.
In the difficult, almost hopeless position is the main character of the film - the venerable and respected Dr. Richard Walker. Arriving with his wife in Paris, both in their business, and in order to remember together the days of his former youth, the man suddenly discovers that his wife was gone. He does not speak French, can not explain anything and no one is going to help him. Only a randomly met street girl, who somehow had his wife's things, will share with the doctor his adventures and dangerous tests. And they are expected, no more - no less, criminal disassembly and confrontation of organized crime on an international scale.
The beautiful actors and the great director Roman Polanski, who does not need to be introduced, allow putting this detective into the "top" category in advance. And after watching the film, you just see it.