A year ago, high school student Laura Barns committed suicide after an anonymous user uploads a humiliating video of her passing out and defecating herself at an unsupervised party.
One year later, Blaire Lily (Laura’s childhood best friend) enters a skype group chat with her boyfriend Mitch Roussel and their classmates Jess Felton, Ken Smith, and Adam Sewell, along with an unknown user named “billie227” on Laura’s death anniversary.
After some unsuccessful attempts to get rid of the unknown user, messages from Laura’s Facebook account are sent to both Laura and Blaire, and the whole group suspects their classmate Val Rommel pranking them.
Humiliating pictures of Val appear on Jess’s and Adam’s Facebook successively, however, Jess and Adam deny themselves posting those pictures.
The unknown user claims himself doing this and starts chatting with the group, at the same time, Blaire found out this Skype account belongs to Laura Barns.
“billie227” sends Val something and Val reacts negatively, calls the police, and hangs up although “billie227” tells her not to do so.
“billie227” sends Blaire a Instagram link with a screenshot showing that Val told Laura to end her own life and refused to take down the humiliating video of Laura.
Blaire wants to quit chatting on Skype and “billie227” told her not to or her friends will all die.
Val is suddenly brought back to the chat sitting next to a bottle of bleach before collapsing. “billie227” types to ask Val kill herself, and police found that Val committed suicide after arrival.
“billie227” says they all have dark secrets and sends each of them one of Blair's secret, which is Blair’s affair with Adam. Mitch tells everyone not to receive, however, Blaire accepts under curiosity.
“billie227” said he wants to play a game, however, Ken uses a program to remove “billie227” from the chat successfully although “billie227” tells him not to.
Adam calls the police, however, it turns out to be “billie227” on the other side and he re-enters the group chat with the camera view, which comes from Ken’s room.
“billie227” makes Ken kill himself using a blender.
Someone knocks on Adam’s door and he starts to panic. “billie227” told him to sit down with mouth shut and forces everyone to play the game “Never Have I Ever” after reshowing Blaire the humiliating video of Laura. He claims that loser in the game dies.
“billie227” starts telling secrets, which reveal their backstabbing against each other and the remaining group starts to fight each other.
Adam becomes impulsive and forces Blaire to commit having affair with him, and “billie227” show the video to Mitch.
Blaire and Adam receive messages sent to their printers and refuse to show Mitch like it is another secret between Blaire and Adam.
Mitch threatens to leave if they insist on refusing to show the messages. At the moment Mitch is trying to leave, Blaire can’t take it and shows the message to Mitch saying if Mitch leaves, Adam will die.
“billie227” makes Adam shoot himself and it turns out that Adam is holding the message saying if Mitch leaves, Blaire will die.
While Blaire convinces Jess not to continue playing, she started reaching for help through Chatroulette. She successfully finds a stranger and asks her to send the police to Jess’s place. But soon after, Jess was killed with a curling iron.
Finally, “billie227” ask Blaire and Mitch to confess who posted the humiliating video of Laura and Blaire wants this to end and tells “billie227” it is Mitch. As a result, Mitch is forced to kill himself with a knife.
The time counting is still going and Blaire desperately tries to stop her and starts reminding her of their closeness when they were kids and apologize for their drifting apart now.
Laura finally revealed her sin that it is Blaire herself who took the video in the first place, and then a pair of hands slam her laptop shut and a spirit lunges at her.