Amanda Weber is a museum employee. Her nephew, Victorien, who feels that wild animals should not be kept in zoos, has been murdered, and she seeks to find out why and how. She knows that Victorien was witness to a mysterious government project where 50 tourists were killed by an unknown poison gas, and the bus they were travelling in was found at the bottom of a lake. Alex, a callous government assassin who is having marital problems with his wife Delphine, has orders to kill anyone who knows about the cover-up of that project, and Amanda soon becomes his target.