Seven friends throw a 1920s–themed party, where it's all pretend—until one of them is murdered. One of Us Is Lying meets Knives Out in this killer locked-room mystery.

Someone brought a knife to the party.

To celebrate the end of high school, Izzy Morales joins her ride-or-die Kassidy and five friends on a 1920s–themed getaway at the glamorous Ashwood Manor. There, Izzy and her friends party in vintage dresses and expensive diamonds—until Kassidy’s boyfriend turns up dead.

Murdered, investigators declare when they arrive at the scene, and now every party guest is a suspect. There’s the girlfriend, in love. The other girl, in despair. The old friend, forlorn. The new friend, distressed. The brooding enigma. And then, there’s Izzy—the girl who brought the knife.

To find the killer, everyone must undergo a grueling interrogation, all while locked in an estate where, suddenly, the greatest luxury is innocence.