Road to Hong Kong (1962)

Ex-vaudevillian con men Chester Babcock and Harry Turner are still making an impression overseas. Sought after by almost every far east country (for fraud), their latest scheme ends up knocking the memory out of Chester's head. While heading to Tibet for an herbal remedy, Diane (a secret agent) mistakes Chester for her clandestine contact and slips him a vital rocket fuel formula. Chester retrieves his memory at a monastery where he's also introduced to a rare herb that induces a photographic memory. Harry, recognizing its marketable potential, steals it, and the two head back to modern civilization with plans to exploit it in a legit memory act, but Diane awaits them, with gun in hand, to retrieve the formula (which Harry burned after having Chester commit it to memory as an exercise). Now her megalomaniac boss wants to meet the boys and dig the secret out of Chester at all costs.