Adventures of Captain Marvel is a 1941 American 12-chapter black-and-white movie serial from Republic Pictures, produced by Hiram S. Brown, Jr., directed by John English and William Witney, that stars Tom Tyler in the title role of Captain Marvel and Frank Coghlan, Jr. as his alter ego, Billy Batson. The serial was adapted from the popular Captain Marvel comic book character then appearing in Fawcett Comics publications Whiz Comics and Captain Marvel Adventures.

Adventures of Captain Marvel was the 21st of 66 film serials produced by Republic and their first comic book character adaptation (not counting comic strips). The serial featured the Fawcett Comics superhero, placed within an original screen story. Captain Marvel fights a masked criminal mastermind called the Scorpion, who is determined to gain control of an ancient weapon. It is made in the form of a large metallic scorpion with adjustable legs, tail, and removable lenses that must be properly aligned in order to activate its powerful ray.

Plot
During an archaeological expedition to Siam’s volcanic Valley of the Tombs to find the lost secret of the Scorpion Kingdom, a device of great power, the Golden Scorpion, is discovered hidden inside a sealed crypt. While examining it, the device’s quartz lenses are aligned and powerful energy beam erupts, causing an explosion, resealing the crypt. This allows young radio broadcaster and expedition member Billy Batson, who obeyed the warning on the crypt’s seal not to enter, to be chosen by the ancient wizard Shazam. The wizard grants Billy the powers of Captain Marvel whenever he repeats the wizard’s name. Captain Marvel’s powers can be used only to protect those in danger from the curse of the Golden Scorpion. The crypt’s entrance is quickly cleared, then Captain Marvel utters “Shazam!” and quickly resumes his Billy Batson alter ego.

The Golden Scorpion’s power lenses are divided among the scientists of the Malcolm Archaeological Expedition so that its power can only be used by agreement of the entire group, who then return to the U. S. after their discovery. An all-black-garbed-and-hooded criminal mastermind, calling himself the Scorpion, steals the ancient device after their return and sets about acquiring the distributed lenses. Several expedition members are killed in the Scorpion’s quest, despite Captain Marvel’s continual efforts to thwart his plan. Deducing that the Scorpion always seems to know what happens during the scientists’ meetings, Billy later confides to his friends, Betty Wallace and Whitey Murphy, his suspicion that the Scorpion may be one of the Malcolm archaeological team.

Discovering that one of the Golden Scorpion’s power lenses was purposely left behind, cleverly hidden in the very crypt where it was first discovered, Billy Batson and the surviving scientists agree it must be retrieved. They return by cargo ship to Siam where, near landfall, they barely survive a typhoon before finally being rescued by Captain Marvel. They eventually retrieve the hidden lens, but it is stolen by the Scorpion. By accident, from a distance, the Scorpion observes Captain Marvel transforming back into Billy Batson. Capturing Billy and gagging him, the Scorpion interrogates him about his secret. Billy’s tape gag is removed when he agrees to talk. “Shazam”! is his only response, and he transforms in a flash of light and smoke into Captain Marvel. The Scorpion’s identity is then revealed to be one of the last surviving scientists, who is killed by a Siamese native who turns the idol’s ray on him, vaporizing him.

Captain Marvel tosses the Golden Scorpion and its power lenses into a volcano’s molten lava to prevent them from ever being used for evil. Upon its destruction, Captain Marvel is instantly transformed back into Billy Batson forever, the danger from the device’s curse having now been eliminated.

Cast
Tom Tyler as Captain Marvel
Frank Coghlan, Jr. as Billy Batson
William Benedict as Whitey Murphy
Louise Currie as Betty Wallace
Robert Strange as John Malcolm
Harry Worth as Prof Luther Bentley
Bryant Washburn as Harry Carlyle
John Davidson as Tal Chotali
George Pembroke as Dr. Stephen Lang
Peter George Lynn as Prof Dwight Fisher
Reed Hadley as Rahman Bar
Jack Mulhall as Howell
Kenneth Duncan as Barnett
Nigel De Brulier as Shazam
Tetsu Komai as Chan Lai
Stanley Price as Owens
Gerald Mohr as the voice of The Scorpion (uncredited)
Ken Terrell as Bentley’s Butler (uncredited)