Plot
From Wikipedia, the free encyclopediaA year after the attack on Lake Victoria by prehistoric piranhas, an eradication campaign has left the lake uninhabitable by life, and the town itself has been largely abandoned as a result of the drying-up of their main revenue source, tourism.
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Maddy (Danielle Panabaker), a marine biology student, returns home for the summer to the waterpark she co-owns. She finds to her horror that the other co-owner, her step-father Chet (David Koechner), plans to add an adult-themed section to the waterpark with 'water-certified strippers', and re-open it as "Big Wet." At a party at the waterpark that night, Maddy encounters several old acquaintances, including her policeman ex-boyfriend Kyle (Chris Zylka), and Barry (Matt Bush) who has secretly had a crush on her since grade-school. She also runs into two of her close friends, Ashley (Meagan Tandy), and Shelby (Katrina Bowden).
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The next day, Maddy is consoling Shelby about their missing friends. While sitting on a jetty, they are both attacked by the swarm of piranhas. They manage to kill one, and Maddy, Kyle and Barry bring it to Mr. Goodman (Christopher Lloyd) to examine. He informs them that the piranhas may be moving via sewage pipes and underground rivers between lakes. The trio return to the lake, where they establish that the piranhas cannot make their way into the outflow pipes connecting the lake and the waterpark.
While Shelby and Josh are having sex, the piranha in Shelby's vagina bites Josh's penis, forcing him to chop the organ off with a knife. Both are hospitalised. Kyle is revealed to be corrupt and taking pay-offs from Chet, who is secretly pumping water from
an underground river into the waterpark.
"Big Wet" opens the next day. Among the first guests are Deputy Fallon (Ving Rhames), who survived his previous ordeal with the piranhas but lost his legs, and former cameraman Drew Cunningham (Paul Scheer). While the duo attempts to overcome their fear of the water after they were attacked a year ago, David Hasselhoff also makes an appearance as a celebrity lifeguard.
Discovering the connection between the park and the underground river, Maddy attempts to shut the waterpark down, but is stopped by Chet and Kyle. The piranhas make their way
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rescuing a small boy, becomes pleased that he has finally become a real lifeguard. In the chaos, Chet is killed by a low-hanging cable after attempting to drive away and escape.
Barry begins to drain the pools; however Maddy, who is rescuing people from the water, becomes caught in the suction and dragged down to the bottom of the pool. After Kyle refuses to save her, Barry, despite being unable to swim, leaps down and brings her to the surface, where they kiss.
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Cast
Danielle Panabaker as Maddy
Matt Bush as Barry
David Koechner as Chet
Chris Zylka as Kyle
Katrina Bowden as Shelby
Gary Busey as Clayton
Christopher Lloyd as Mr. Goodman
David Hasselhoff as himself