While on their way to a fishing destination, four friends discover a secluded lake and are unaware that a huge serpent-like creature is lurking in the water. After their boat becomes marooned on the middle of the lake, the last remaining individual discovers that the vessel is slowly sinking. With communication down, the stranded fisherman must figure out how to get back to shore before the boat sinks all while avoid being devoured by the aquatic monstrosity swimming below.