One night, while teenagers Bailey, Mick, Jade, Aaron, Keith and Violette take part in an online group chat session, they are suddenly joined by a user known only as "Bonnie716." Thinking it's just a technical glitch, the friends carry on their conversation... until Bailey begins receiving messages from someone claiming to be Lola Bowers, a classmate who killed herself exactly one year prior. As Bailey tries to expose Bonnie's identity, her friends are forced to confront their darkest secrets and lies.