P4: are the new recruits in the violent crimes unit at Gangnam Police Station. The journey of four young cops as they fumble, learn, fall in love and find their way to becoming people the citizens can trust.

A group of friends run a popular travel vlog that helps fund their adventures. The leader of the group brings along her younger sister for the next scuba diving trip to an isolated cove. But when their plane crashes, the two sisters must use their strength, resourcefulness and immense courage to survive a pack of great white sharks.