Continuation: King Kong vs. Godzilla (続 キングコング対ゴジラ Zoku Kingu Kongu tai Gojira) is an unmade 1963 direct sequel to King Kong vs. Godzilla.
After a plane crashes in Africa, Nichio Products employee Nomura leads a search party. The assignment is personal: his girlfriend Mitsuko's older brother was on the plane, along with his wife and child. After coming across the ruins of an ancient civilization, he finds only the child, under the protection of King Kong. While trying to rescue the infant, Nomura encounters a Giant Scorpion, who soon does battle with Kong. The gorilla prevails by crushing it with a rock, while Nomura grabs the baby and escapes via helicopter. Unbeknownst to him, Kong gives chase.
Mitsuko's friend Yoshie is dating Tsukida, who works for Amusement Center KK. His next project is Hinomaru Land on the Seto Inland Sea. After much contemplation, he hits upon the park's centerpiece: the remains of Godzilla, who Kong killed off the coast of Atami. A diver finds him in a sandbank, perfectly preserved by the low temperatures of Sagami Bay. After veterinarians confirm he is not breathing, he is tranquilized and shipped to the park. Having returned to Japan, Nomura decides with Mitsuko to raise the child as their own, but Kong hasn't given up his pursuit. After shaking a passenger ship in the Taiwan Strait and rescuing another baby, a U.S. Navy fleet fires on him. Their weapons have little effect, but he smashes a destroyer before departing. Realizing Kong's goal, the couple takes refuge at Nomura's family home near Lake Biwa. Meanwhile, rival company Amusement Development KK sets off a bomb near Godzilla, restarting his heart, though it soon stops again. King Kong makes landfall in Kitakyushu, destroying the Wakato Bridge. The JSDF tries their old strategy of exploding rockets filled with Farolacton above him, but a typhoon blows the mist back towards the soldiers, knocking them out.
The JSDF decides to revive Godzilla to fight Kong, though electric shocks fail to rouse him. Kong's arrival forces them to withdraw, but he inadvertently sends enough electricity through Godzilla's body to restart his heart. The King of the Monsters lands a tail-whip and blast of atomic breath before Kong gets his bearings. They duel, but agree to withdraw for a day to recover. The JSDF lures Kong away from Tokyo by flying Nomura, Mitsuko, and the baby to Kagoshima Airport. At the same time, they draw Godzilla out to sea with a rubber replica of Kong filled with a deadly gas. He bites into the decoy and vanishes amidst the explosion.
Nomura tries to seek asylum for his family, but every country he asks turns him down, fearing Kong will attack them next. Kong comes ashore in Kagoshima, destroying the airport as Nomura, Misuko, and the baby drive to Fukuoka. Godzilla bursts out of Mount Aso's caldera in front of them, blocking their path. They flee on foot as Kong arrives to challenge Godzilla. An earthquake causes the volcano to erupt. Both monsters save the child: Godzilla on accident, his atomic breath destroying a magma flow headed towards them, and Kong on purpose, carrying them to safer terrain. As Mitsuko and Nomura reunite with their baby, Godzilla and Kong are consumed by the eruption, their fates unknown.
