Perry assists Nhi Khanh in finding her presumed dead husband, Ben Porter, a war correspondent who vanished after their marriage in Vietnam. Drake, tailing a suspicious observer of Perry, traces him to Clinton Exeter's political headquarters, where he spots a man resembling Ben before he disappears. Perry learns Ben's true identity: Royce, a bigamist who deceived Nhi.

Private detective Paul Drake goes undercover as a prison convict to help Perry Mason develop the evidence needed to prove that his client, a prisoner at the penitentiary, did not call one of the guards.