개: dog eat dog(2015)

There are 'dogs' that target Koreans while they're on vacation abroad. Hyeong-sin and Ji-hoon kidnap and kill these people without a drop of guilt. While they are in Korea for a period of time, the family of the people kill chase after them like dogs that never let go once they bite. Doo-jin, who is abandoned by Hyeong-sin's gang, kidnap a new victim alone. A middle-aged woman tracks down Hyeong-jin's gang to find her son who went missing during his vacation. However, the victim and kidnapper are tangled in many complicated ways...