Doraemon the Movie: Nobita and the Castle of the Undersea Devil

In a thrilling summer adventure, Nobita and his friends dive into the depths of the Pacific Ocean, embarking on a quest filled with excitement and peril. When Jaian and Suneo commandeer Doraemon's advanced underwater vehicle, they set off in search of a legendary treasure ship, unaware of the dangers that lie beneath the waves. As they navigate the ocean's mysteries, the protective capabilities of Doraemon's environment gun begin to wane, leaving them exposed to the treacherous sea.

Their journey takes an unexpected turn when they encounter the inhabitants of the underwater kingdom of Mu, only to find themselves captured. Meanwhile, a grave threat looms from another underwater realm, Atlantis, now under the control of menacing robots. Mistaking a volcanic eruption for an attack, these robots prepare to unleash nuclear devastation upon the world. With the assistance of a brave boy from Mu, Nobita and his friends rally to thwart this impending disaster. As they face overwhelming odds, Doraemon's underwater vehicle makes a heroic sacrifice, turning the tide in their favor and ensuring a return to Mu as celebrated heroes.