He is first seen with Red, whilst flirting with Maya. Malik attempts to punch Red. Due to the event, Dennis appears. He talks to Sara.
Later, he explained that he seeks revenge on her and her friends for coming back to the lake. When Sara was 18, in the movie she is 21, Sara accidentally cuts Dennis' face, leaving a scar.
When Malik gets attacked, Dennis takes Gordon and Beth with him to look for help. Not long after they set sail, the boat stops. Gordon and Beth are confused. Dennis asks Gordon to go in the water. Gordon refuses. Gordon keeps saying no, until Dennis shoots him into the water.
Gordon sees the shark coming towards him. Gordon, attempts, to climb the tree. But, the shark gets him. When on the boat, again, Beth, scared straight, sits on a box. Dennis and Red puts a camera in the water. Beth asks why. Dennis explained that this is a net filled with cookiecutter sharks. Dennis, eventually, pushes her in to the net, to be killed by the cookiecutter sharks.
Later in the movie, Crim traps Sara in a cage; under her is a Shortfin mako shark. Dennis leads the cage into the water. Nick, escaped from the sheriff, tries to save Sara. He succeeds, and the shark eats Crim.