A bestselling young adult mystery thriller by Karen M. McManus that combines the intrigue of a classic whodunit with the drama of a high school setting.

Five students walk into detention at Bayview High: Bronwyn, the brilliant overachiever; Addy, the popular homecoming princess; Nate, the rebellious delinquent; Cooper, the star baseball player; and Simon, the creator of the school's notorious gossip app. But only four of them leave alive.

When Simon suddenly dies from a severe allergic reaction during detention, the police suspect it wasn't an accident. Since each of the remaining students had a motive to silence Simon before he exposed their biggest secrets, all four become prime suspects in a murder investigation.

As the case unfolds, hidden truths, betrayals, and unexpected alliances emerge. Told through multiple perspectives, the novel keeps readers guessing while exploring themes of identity, reputation, friendship, prejudice, and the pressure of living up to others' expectations.

Fast-paced, emotionally engaging, and packed with twists, One of Us Is Lying became an international bestseller and launched a successful series.