Jennifer, uma popular líder-de-torcida linda (Megan Fox), é sacrificada injustamente pelo líder de uma banda, que faz um pacto com diabo para conseguir lançar um CD. Eles pensavam que ela era virgem, mas erraram. Jennifer acaba sendo possuída por um demônio e acaba tendo que se alimentar de sangue humano, sacrificando garotos para se satisfazer.

Jennifer's Body is a 2009 dark comedy and horror film written by Diablo Cody. The film is directed by Karyn Kusama, and stars Megan Fox as the title character, Amanda Seyfried as her best friend Needy, and Adam Brody as the antagonist Nikolai. It is scheduled for theatrical release in the United States and Canada on September 18, 2009.

Jennifer Check (Megan Fox) is the sexy, popular captain of the high school cheerleading squad. All of the girls want to be friends with her, and all of the boys want to have sex with her. Jennifer's friend since childhood, Anita "Needy" Lesnicky (Amanda Seyfried), is a nerdy, substantially less popular, "plain jane" student. Jennifer ends up as the sacrifice in a Satanic ritual, held by a rock band, hoping that the sacrifice will increase their chances of getting a record deal. The ritual goes horribly wrong, causing Jennifer to get possessed by a demon and start feeding off of the boys in her high school; First seducing them to get close, and then consuming them in a manner similar to that of a Succubus. It becomes Needy's goal to stop Jennifer from killing more of her classmates.

Megan Fox ... Jennifer
Amanda Seyfried ... Needy
Johnny Simmons ... Chip
Adam Brody ... Nikolai
Sal Cortez ... Chas
Ryan Levine ... Mick
Juan Riedinger ... Dirk
Colin Askey ... Keyboardist
Chris Pratt ... Roman Duda
Juno Ruddell ... Officer Warzak
Kyle Gallner ... Colin Gray
Josh Emerson ... Jonas Konelle
J.K. Simmons ... Mr. Wroblewski
Amy Sedaris ... Needy's Mom
Cynthia Stevenson ... Chip's Mom