Olive (played by Emma Stone) is a smart, witty high school student who is more interested in books than boys. However, when she lies to her best friend Rhiannon (played by Aly Michalka) about losing her virginity, her world suddenly changes. The rumor spreads like wildfire through the school and soon everyone thinks that Olive is promiscuous.
At first, Olive is annoyed by the rumors but decides to embrace her newfound popularity by letting more guys pretend to have sex with her. However, this only makes things worse as her peers start to turn on her and the school board gets concerned about her behavior. Even her favorite teacher Mr. Griffith (played by Thomas Haden Church) and guidance counselor Mrs. Griffith (played by Lisa Kudrow) start to distance themselves from her.
Through it all, Olive's parents (played by Patricia Clarkson and Stanley Tucci) are her biggest supporters. They are quirky and eccentric but always there for their daughter when she needs them. Olive also finds support in her long-time crush Todd (played by Penn Badgley) who sees through the rumors and likes her for who she really is.
In the end, Olive decides to take on the rumor mill and clears her name once and for all. She gives a speech at a school assembly, revealing the truth about the rumors and apologizing for her role in perpetuating them. Olive learns that being true to yourself is more important than fitting in and that the people who truly care about you will always be there no matter what.