Solo goes to India to investigate the death of a fellow U.N.C.L.E. agent in an airline crash, and discovers that a cult of Thuggees headed by a maharajah (Murray Matheson) is causing the crashes in order to loot the passengers. But Solo and THRUSH agent Tom Simpson (Linden Chiles) are looking to recover one item in particular - U.N.C.L.E.'s new polygraph device.