A group of high school friends receives a sinister chain letter via email, warning them to forward it to others or face deadly consequences. Ignoring the message as a harmless prank, the friends soon find themselves targeted by a sadistic killer who uses the anonymity of the internet and chains to gruesomely eliminate those who break the chain. The police, including a seasoned detective, struggle to unravel the mystery behind the deaths as they tighten the circle around the culprits, but the body count continues to rise.

As the students begin to take the chain letter more seriously, paranoia spreads throughout the school, leading to accusations and distrust among friends. The desperate attempts to forward the chain letter and save themselves only plunge the survivors deeper into the killer's twisted game. Faced with relentless terror and mounting dread, the friends must decipher the origins of the chain letter and find a way to break the cycle before they all fall victim to the unseen menace.