One of Us Is Lying starts off in a typical after-school detention with five students suffering through the punishment. But while five students start off in detention, in a few short minutes, only four students walk out alive, one is dead. The students thought that detention was the worst thing that could happen, but they soon realize that one of them is going to be blamed for this death.
Simon, the boy who died, was not very well liked, as he was the owner of an app that spilled gossip and secrets about the other students at the school. He was set to press 'submit' on an entry that would spill the deepest secrets of the other four students in detention that day. These students were:
- Bronwyn- the over-achiever who has her sights set on going to Yale
- Cooper- the athlete whose pitch is going to lead him right to the Major league
- Nate- the rebel who already has a police record
- Addy- the popular beauty queen who works very hard at always being perfect.