Upon discovering his fiancée Tollea has been kidnaped, Ramu and his friend Kado set out for a Pacific isle where all strangers are to be killed on arrival and the inhabitants, who are frequently sacrificed to an angry volcano god, worship the cobra. The island is ruled over by Tollea's evil twin Naja, the Cobra Woman, who, besides having designs on her new prisoner Ramu, also desires to eliminate any competition from her benevolent sister.
Synopsis by IMDb

May 18, 1944
THE SCREEN
By BOSLEY CROWTHER
That beautiful land of nowhere which Universal has carved out of the blue for the recently recurring caprices of Maria Montez, Jon Hall and Sabu again rocks to exotic music, the solemn boom of gongs and the rumble of the great Fire Mountain in "Cobra Woman," which came to Loew's Criterion yesterday. And again the submissive audience is witchingly rocked to sleep with as wacky an adventure fable as was ever dished up outside the comic strips. For the story of Cobra Island is being hissed through Universal's glittering teeth—glittering, that is, in Technicolor. And anybody who doesn't believe it can take a hike.
Cobra Island, we hasten to inform you, is ruled by a viperous doll who snake-dances in the sacred temple, surrounded by a bevy of night-gowned toots. She also sends levies of her subjects to be tossed into the fire, and generally behaves so that no one will vote her the most-popular-girl in her class. So it is not in the least surprising when a hurry call is sent for her beautiful and gracious twin-sister to come home from someplace else and grab the throne. It is not in the least surprising—and not in the least out of line—that the good one should be accompanied by her ardent fiancé, Mr. Hall, himself appropriately accompanied by Sabu and a chimpanzee. And it is not in the least implausible—provided you're with us up to now—that the whole kit-and-kaboodle should fight like wildcats before the island is finally freed.
Do you want to know any more about it? Do you want to know that Miss Montez plays dual roles—those of the good twin and the bad twin—without a trace of distinction between? Do you want to know that the Dance of King Cobra is howling honky-tonk and that the intelligence level of the whole thing is that of the chimpanzee? If you do, we solemnly counsel that you go to see the film. It is better than the funny papers, on which it was obviously based.
Snakebite Remedy
COBRA WOMAN, screen play by Gene Lewis, and Richard Brooks; from an original story by W. Scott Darling; directed by Robert Siodmak; produced by George Waggner for Universal. At Loew's Criterion.
Tollea . . . . . Maria Montez
Nadja
Ramu . . . . . Jon Hall
Kado . . . . . Sabu
Hava . . . . . Lon Chaney Jr.
Martok . . . . . Edgar Barrier
Queen . . . . . Mary Nash
MacDonald . . . . . Moroni Olsen
Veeda . . . . . Lois Collier
Father Paul . . . . . Samuel S. Hinds
Dancer . . . . . Carmen D'Antonio

Cobra Woman is a super-fantastic melodrama backgrounded on a mythical island that might exist somewhere in the Indian Ocean. Elaborately and colorfully mounted for constant eye-appeal, and with the starring trio of Maria Montez, Jon Hall and Sabu, picture unfolds at fast pace to concentrate on action features of the tale.

Of Ms Montez, then, and her inimitable spangles-and-cardboard epics it can be most truly said----
They don’t make ’em like that any more.

Adventure filled with spectacle and brilliant color.

A deliciously detestable Hollywood relic; a bad movie that knows how to be good.
<