This story is about people hiking in the remote part of a Hawaiian island while a killer is in the area. Steve Zahn plays the lead character of Cliff and Milla Jovovich plays Cydney his wife. We see a portion of a video from a wedding reception and realize the two are newlyweds on their honeymoon. They plan to hike to part of the island that is very isolated. They stop at a grocery store to buy supplies and to pay for their hiking permits. On the drive to the start of the hiking trail, they see another couple Kale (played by Chris Hemsworth) and Cleo (played by Marley Shelton) hitchhiking. Cliff wants to give them a ride by Cydney is afraid of how they look. Kale is very intimidating, so Cliff thinks he made a mistake stopping for them. They say they are going to the beach. It is clear that Cliff is judging them for the way they look, which makes Kale angry. Cliff says sorry but they are driving the other direction which is a lie, to make an excuse for not giving them a ride. Cleo tells Cydney they just got married and shows her some wedding photos, which helps break the tension. Cliff offers them a ride, but Kale refuses. It is very uncomfortable. Cliff and Cydney drive away, leaving them to get a ride from someone else.
Cliff and Cydney get to the trail, leave the car behind, and start hiking. When they come upon a very dangerous part, they run into another hiker Nick (played by Timothy Olyphant) who shows them how to cross safely. Cliff makes it across, but Cydney almost falls when startled by a helicopter that suddenly shows up. Nick catches her to keep her from falling. Further along the trial, they run into some other hikers who tell them that a couple was murdered on the other island of Oahu, which the authorities are having trouble identifying because their teeth were pulled and their fingertips cut off. They say the helicopter activity is because police are looking for the murderers, which they think are a couple, and they may be on this island now.
On the trail, they meet up with Nick's girlfriend Gina (played by Kiele Sanchez) who is sunbathing by a waterfall in the buff. They go skinny-dipping. They also run into Kale and Cleo. Cliff is surprised to see Kale, because Kale said they were going to the beach nothing about the trail. Cliff starts to worry that they are following him, as Kale is obviously still angry because of Cliff's lying to him. Nick hunts and kills a wild goat by hand. Gina cheerfully helps gut it. This gives Cliff and Cydney the creeps because maybe Nick and Gina are the killers. They are relieved the next day when the police arrest Kale and Cleo, when they find human teeth in Kale's bag.
Cliff gets some kayaks. He says he borrowed them from some other hikers. He invites Nick to go with him to a cave. Out of curiosity, Gina watches the wedding video that is supposed to be of Cliff and Cydney. She is shocked that it is different people. She realizes the killers are Cliff and Cydney. She tries to warn Nick, but it is already too late. Cliff attacks Nick by shooting him in the back of the head. Cydney attacks Gina with a knife. They fight. Gina is able to throw Cydney into the cave. Cliff tells Cydney to go to the beach. Cliff goes after Gina. They fight. Gina stabs Cliff in the hand so he cannot fire the gun.
Nick was knocked unconscious, but escapes death because he has a metal plate in his head from being a soldier and it stopped the bullet from entering his brain. When he comes to, Nick goes to help Gina. When he gets there, he struggles with Cliff. Cydney gets the attention of a police helicopter, which picks her up from the beach. She tells them she knows where the real killers are. They fly over where Cliff and Nick are struggling. Nick has taken the gun away from Cliff so it appears that Nick is the killer. Cydney hesitates, but then tells police that Cliff is the killer and that he forced her to participate in the other killings. Cliff gets the gun back but because of the stab wounds in his hands, he cannot fire it. The police shoot him. Nick and Gina both survive.
Best part of story, including ending:
The misdirection in the beginning is really clever. The nerdy couple looks like they are in danger from all the other ones, so it is very surprising when they turn out to actually be the killers.
Best scene in story:
I like the flashback scene where the real killers are revealed where it shows Cliff planting the evidence of human teeth in Kale's bag so the wrong guy is arrested. This is a good reveal.
Opinion about the main character:
The couple on their honeymoon seem so normal until we realize they are psychopaths. It is very startling and suspenseful.