A lone survivor of a shipwreck washes up on Blood Island. William Fitzgerald (Richard Derr) is found by Dr. Charles Girard (Francis Lederer), a scientist who has set up a laboratory on the island with his wife, Frances Girard (Greta Thyssen), and assistant Walter Perrera (Oscar Keesee). The island's natives are scared of Dr. Girard, due to his strange ideas about the link between man and animals, and leave the island. The doctor has experimented on a panther, changing it into a half-man/half-panther beast which escapes and goes on a rampage. Fitzgerald and Frances fall in love and have to deal with the escaped creature, the mad Dr. Girard and the sadistic Walter. The creature is recaptured but escapes again, killing Walter and Dr. Girard before falling off a cliff.
The working titles of the film were Creature from Blood Island, The Gory Creatures, Island of Terror and Gore Creature. According to the onscreen credits, the film was shot entirely in Manila, Philippines.