What movie is this?!??1!?!?

ive been wondering for awhile now cause i loved this movie. Ok so a couple are going to hawaii for there honey moon and they meet another couple once they here a couple of serial killers got loose. they go for a while and the honey moon goers find that the other couple they are with are the serial killers and try to escape, they end up killing them. the one honeymoon guy was in the military and he had a metal plate in his head that saved his life. hope you can help cause i wanna see this movie again!