After a week stranded on the ship following a zombie outbreak, the group has set up supplies and limited communication with the outside world. The protagonist calls home, learning the infection has reached their village, where family members barricade themselves for safety. During a quiet night watch on the ship, a sudden thud under the hull startles everyone. Rushing to the cockpit, they discover a massive, mysterious shadow moving beneath the water on the surveillance feed, signaling a new and unknown threat approaching the ship.