Eden Lake - (2008)

When nursery teacher Jenny (Kelly Reilly) escapes to the country for a relaxing weekend away with her boyfriend  (Michael Fassbennder) she is unaware of a romantic surprise he has in store. The location is perfect. A lake enclosed by woodlands, seemingly deserted. But before the happy couple can enjoy the retreat, their peace is shattered by a gang of violent youths. What begins is a shocking and unrelenting game of cat–and–mouse, as Jenny is forced to fight back against her aggressors.