According to Deadline,
One of Us Is Lying.
Based on the best selling young adult novel of the same name by author Karen M. McManus, the series focuses on five high school students, all of whom walk into detention together.
Only four of the five make it out alive though. When everyone winds up a suspect following the events of detention, it soon becomes clear that everyone has also got secrets they’re trying to hide.
For his part, McKenna will take on the role of Simon for the forthcoming series adaptation.
Simon is described as a brainy outcast whose claim to fame is being the creator of a gossip app the entire school seems to be obsessed with. He takes pride in posting juicy, and often cruel, tidbits of gossip in an effort to expose his fellow classmates as the “liars and hypocrites they really are.”