Imposters have infiltrated Gameston Castle to steal the Earl of Simpleton's treasures. But who is an imposter and who is a genuine guest? Imposter! is a lively after-dinner game in which players use debate, bluffing and logic to win points. Genuine guests will try to unmask imposters, while the imposters, risking revealing their true identities every time they do so, will try to smuggle the Earl's precious possessions out of the castle. Can the imposters avoid detection and steal the treasure? or will the honest guests unmask them?