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.