"Mystery of Thug Island" is basically a good, romantic adventure story and it boasts the presences of both Guy Madison and Giacomo Rossi-Stuart. Both actors are almost unrecognizable playing handsome Indian characters, the former as the villainous high priest of the blood drinking goddess Kali and the latter as a lowly native snake-hunter. This version is far superior to the awkwardly stultifying 1954 Lex Barker version "Mystery of the Black Jungle" or "Black Devils of Kali" with which it is often confused. The most unlikely and unrealistic part of the plot is Ada's 19th century British pater approving of her marriage to the low-caste native Tremal Naik after he's finally found her after her 15 years of captivity. Not bloody likely! The thughi cult is a fascinating subject better treated in film by "Gunga Din" (1939), "Stranglers of Bombay" (1960), and "The Deceivers (1988, all of which contain much better portrayals.