then uses his hat, which turns into be a subterranean room that can move, causing Eru to lose sight of them. However, the fish craft suddenly attacks Eru, shooting his ship. Gian rushes out with the group to save Eru, but it caused him to be arrested and given the death sentence for crossing the border. While the group is put in a cell, Eru tries to defend them in a trial, which got interrupted by a ship crash landing. It is revealed that another undersea kingdom, Atlantis, now controlled by robots, was about to destroy the Earth with nuclear weapons after mistaking a volcano eruption for an invasion. After convincing the Prime minister, Eru sets the group free and went on a journey with them into Atlantis, which is in the Bermuda Triangle. After bypassing a fleet of fish craft and the barrier that leads into the kingdom with Doraemon's hat, they went on to search the "Devil's Castle", where Atlantis' main computer, Poseidon, is at. But having difficulty looking for it, Shizuka allows herself to be captured by Poseidon's iron guards, a bipedal fish robot, so the group can follow it as she's taken to the castle. Using Doraemon's weapon gadgets, the group enters the castle, facing hordes of iron guards, and while Shizuka is brought upon Poseidon, they got separated. Doraemon fell from a high place, while Eru, Nobita, Gian, and Suneo got captured by the iron guards. Just as Poseidon about to sacrifice Shizuka, thinking it will stop the volcano, Doraemon stops it, but fell unconscious shortly. As Shizuka cries over the robot, Buggy suddenly appears from Doraemon's pocket, and goes straight into Poseidon, crashing and destroying both of them. With Poseidon destroyed, the iron guards stops working, allowing Shizuka and Doraemon to rescue the others and leave before the erupting volcano destroys the castle. After returning to Mu, Doraemon and his friends are hailed as heroes. The story ends after Shizuka looks at one of buggy's screws, and the group saying farewell to Eru. Cast Release The film was released in Japan on March 12, 1983. References External links JMDB entry Films directed by Tsutomu Shibayama 1983 films 1983 anime films Nobita and the Castle of the Undersea Devil Films scored by Shunsuke Kikuchi Films set in Atlantis 1980s Japanese-language films 1980s children's animated films Japanese children's fantasy films