Doraemon: Nobita and the Castle of the Undersea Devil

Nobita and his friends decide to spend the summer holiday under the sea. They go down to the floor of the Pacific with Doraemon's gadgets and set up a camp there. When Gian and Suneo take the submarine and go looking for a sunken treasure ship, they get lost. The group that goes after them comes upon the remains of a civilisation nobody knew about at the bottom of the ocean, and a defence system that is still running. It is the fourth film in the Doraemon cinema series and one of the darkest in it. The story starts as a children's adventure but ends up about war and sacrifice; as in some other entries in the series, one character does not come back. Tsutomu Shibayama directed. Atlantis and lost-civilisation motifs were used often in Japanese children's cinema of the eighties; this film is one of the most remembered examples of that strand.