Three women Lisa (Sian Breckin), Kim (Jaime Winstone) and Tammi (Nichola Burley) while spending a holiday in Mallorca, Spain meet four young men, Bluey (Tom Burke), Josh (Julian Morris), Sean (Robert Boulter) and Marcus (Jay Taylor), who invite them to their yacht, who take the girls out to sea. While they are out on the ocean they take drugs, the conversation turns to sex and in particular, types of sexual acts. One of the men describes a sex act called a "donkey punch" which involves a penetrating partner punching a receiving partner in the back of the neck while having "doggy-style" sex in order to increase sexual pleasure for the man.
Three of the men and two of the women begin having sex as one of the men begins to film it. Josh gives Lisa a donkey punch on Bluey's encouragement, it breaks her neck and kills her. The men decide to throw the body overboard, the women want to report it. Lisa's body is thrown overboard while they argue about the tape of the incident. Bluey insults Tammi and in a fit of rage she stabs him. Kim and Tammi escape from the men and get on the lifeboat, Tammi fires a flare which attracts the men's attention, they pick the girls up. while the boats are beside each other, Kim shoots Marcus in the stomach with a flare which kills him. It is then revealed that Bluey still has the tape. Josh tortures him, while pressing the knife further into the wound, in order to find out where the tape is. Bluey tells him that Tammi has already taken it. Josh then kills Bluey, Kim brutally kills Sean with the propeller of an outboard motor, wrongly thinking he was threatening Tammi, while in actual fact, he was trying to help her. Kim then commits suicide by jumping overboard, leaving just Josh and Tammi to escape the yacht. Tammi, taking a covert hold of the end of the coiled stern mooring rope and keeps hold as the yacht powers away. In the tender Josh produces a hunting knife while demanding the tape which Tammi has in a waterproof case. Tammi throws this to the floor of the tender to distract Josh. As he reaches for it, Tammi places the looped end of the rope around his neck. He is immediately pulled overboard while the rope (attached also to the yacht) comes under tension and snaps his neck. The yacht powers away with the rope pulling him along behind it. Tammi then fires a flare as the film ends.
