The story picks up about a month after the dramatic finale of the previous film and follows the further adventures of filmmaker Carl Denham (again played by Robert Armstrong), now implicated in numerous lawsuits following the destruction wrought by Kong. Denham leaves New York with the captain of the "Venture", Captain Englehorn, who is certain it is just a matter of time before he is similarly served. Their efforts to make money shipping cargo around the Orient are less than successful. In the Dutch port of Dakang, they run into Nils Helstrom, the former Norwegian skipper who sold Denham the map to Skull Island, who tells them there is a treasure on the island. Blinded by their financial situation, they believe him and agree to return. In fact, he is lying so they will take him to another jurisdiction, as he has just caused a man's death. Shortly after they put out to sea, a beautiful stowaway girl (Helen Mack) is found on board. She had been part of a traveling show run by her recently deceased father, Helstrom's victim.
They arrive at Skull Island where they meet, befriend, and are ultimately saved by Kong's easygoing albino son Kiko (a name used in production but never spoken in the film; he is referred to only as "Little Kong" and, by Denham, "Baby"). The son of Kong is portrayed as considerably smaller than his famous father, but is still twice the size of a man. He is much friendlier and saves Denham and the girl from a giant cave bear. Despite the fact that Helstrom made up his story on the spot out of desperation, a treasure is found. Shortly afterwards, Kiko, Denham and the girl are attacked by a Nothosaurus which Kiko kills, while Helstrom tries to escape in the lifeboat but is eaten by an elasmosaurus. Eventually, Kiko dies saving Carl Denham, as does every other creature on Skull Island, when an earthquake strikes the island and it sinks into the ocean.
The film was produced and released in 1933, immediately following the success of King Kong (1933), and was a modest success. Script writer Ruth Rose intentionally made no attempt to make a serious film on the logic that it could not surpass the first. She stated "If you can't make it bigger, make it funnier." For his part, Denham's actor, Robert Armstrong, preferred the second film, saying that the sequel offered more character development for Carl Denham.
The script/screenplay featured scenes of tribal warfare and a climatic dinosaur stampede during the massive cyclone/earthquake that sinks Skull Island at the film's end. The stampede was going to utilize the models that had been built for Creation (1931) (most being used in the earlier King Kong). However these sequences were never filmed due to the films tight budget and shooting schedule.
Several models which were used for King Kong were also utilized for the production of The Son of Kong. The "long face" Kong armature, from the log bridge and tyrannosaur fight sequences, was also used for "Little Kong". It is the only known model of Kong still in existence and is currently owned by film historian and collector Bob Burns. Also, the same Brontosaurus model used for the raft scene in King Kong can be glimpsed in the sea as the island is sinking. The stop motion animation in the film (done by Willis O'Brien who also did the effects in King Kong) is not as extensive as in the original, but is notable for a sequence where a Styracosaurus chases the explorers through the jungle. Today, the original Styracosaurus model is owned by director Peter Jackson, who remade King Kong in 2005.
- Robert Armstrong as Carl Denham
- Helen Mack as Hilda Petersen
- Frank Reicher as Captain Englehorn
- John Marston as Nils Helstrom
- Victor Wong as Charlie
- Edward Brady as Red
- Noble Johnson as Native Chief (uncredited)
- Steve Clemente as Witch Doctor (uncredited)
- Clarence Wilson as Hilda's father (uncredited)
Kiko: Kong's albino son who is half his size and much friendlier that ends up being drowned when the island is destroyed but saves Denham first. He is named only by fans.
- Styracosaurus: chases Charlie, Englehorn, and Helstrom into a cave and destroys their gun. Same model used in the original film.
- Triceratops: Seen in a deleted scene.
- Cave Bear: chases Denham and Hilda before being driven off by Kiko.
- Nothosaurus: weird reptilian creature that attacks Denham, Hilda and Kiko after they uncover the treasure, only to be killed by Kiko. It seems to resemble a large Protorosaurus.
- Elasmosaurus: devours Helstrom when he attempts to escape in the lifeboat. Jaw snapping was similar to the Apatosaurus snapping in the previous King Kong. It reappears when the island is sinking.
The Son of Kong was released on VHS by Nostalgia Merchant in the 1980s and again in 1991 by Turner Home Entertainment.
In 2005, it received a DVD release and was available both by itself and as part of a collector's set alongside King Kong (1933) and Mighty Joe Young (1949), with commentary by Ray Harryhausen. This film, like the original was colorized for television.