A Perfect Getaway (2009) [ch4cal]

On Hawaiian honeymoon, Hollywood Screenwriter Cliff Anderson and his bride Cydney go from Honolulu to pristine island Kaua'i for an adventurous hike in the nature reserve, for which Cliff forgets his permit in the supply store. Reluctance to give macho Kale and his girl Cleo a ride creates tension that remains when they meet on the trail, with a third couple taking the lead: studly special forces Irak veteran Nick, who even hunts wild goats, and his equally exhibitionist steady girl Gina. Receiving the news that a serial killer who murdered a couple on Oahu probably passed to the island, as they did, starts the couples mistrusting each-other. Furthermore they seem to be followed by mystery stalkers, as turns out of two kinds. After the battle of whit, a bloody struggle for survival is inevitable: the killer is among them and strikes, despite a police helicopter searching for him.