Piranha 3D

A fisherman on Lake Victoria is dragged under and devoured when an underwater tremor cracks open a fissure on the lakebed, releasing a swarm of prehistoric piranhas. Sheriff Julie Forester struggles to keep order over the spring break crowds while her teenage son Jake ditches his babysitting duties to work as a location scout for sleazy soft-porn director Derrick Jones, joining him on a boat with his crew and Jake's crush, Kelly.

Julie partners with a team of visiting seismologists to investigate. They discover the fissure connects to a vast underground lake teeming with the fish. A diver sent down is shredded; the captured specimen is identified by an eccentric ichthyologist as a species thought extinct for two million years. The entire lake is now infested.

Julie tries to evacuate the shoreline but the partying crowds ignore her. The piranhas surge into the swimming masses in a prolonged massacre — swimmers are stripped to bone, a parasailor is decapitated, hundreds are torn apart in churning red water. Deputy Fallon makes a stand on a sinking boat, swinging a broken outboard motor like a weapon, and is dragged under.

Out on the lake, Jake, Kelly, Derrick, and the surviving crew are trapped on Derrick's sinking boat. Derrick is bitten in half from below as he tries to escape. A zipline and a passing speedboat get the survivors to shore, where Jake also rescues his two stranded younger siblings.

As Julie and the kids regroup on the beach, the seismologist Novak warns that the swarm they killed was only the babies — the adults are still down in the underground lake. A massive piranha breaches the water and grabs him before the film smash-cuts to credits.