Claire Forrest seeks her kidnapped scientist father, hidden somewhere on Mystery Island. He is held and forced to work on diabolical inventions by Captain Mephisto, a costumed villain.
as Lance Reardon
as Claire Forrest
as Capt. Mephisto
as Sidney Brand
as Prof. William Forrest
as Prof. Harry Hargraves
as Edward Armstrong
as Frederick "Fred" Braley
as Paul Melton
as John Raymond
as Police Insp. Reed
as Ruga
as Barker / Ritter / Lewis / Frazier / Sardon
as Lyons / Bailey
as Spencer Harvey
