Nursery teacher Jenny (Kelly Reilly) and her
boyfriend Steve (Michael Fassbender) are off for a romantic weekend getaway.
Steve, who is planning to propose, has found just the perfect setting: an abandoned quarry that has been flooded and turned into the picturesque and
peaceful Eden Lake, a hideaway enclosed by woodlands soon to be turned into a luxury housing-estate. After spending an uncomfortable night at a bed and breakfast full of drunk and brawling locals and their noisy children the head off to the seemingly peaceful lakeside. Soon their idyll is interrupted by a gang of unruly youths and their more than intimidating Rottweiler. Steve, ever the responsible adult, does not care the least bit for their load music and their drinking and has a few pointless words with them. Tension mounts, but eventually the kids pack up and leave...until the next day.
While the couple is away enjoying the nature, the teens return, rummage through their belongings and steal Steve´s car, leaving the poor holiday-makers completely stranded. When the enraged adults finally track down the little criminals, Steve confronts them, one word leads to the other and a fight breaks out in the course of which Steve accidentally kills the teens´ dog. The youths manhandle Steve, tie him to the stump of a tree and start to exact their bloody revenge. Fleeing for help, Jenny is subject to a cruel and relentless game of cat-and-mouse as she tries to evade the gang of pursuers, save her
boyfriend and find a way out of the woods...