Nobita is set on hunting pirate treasure, and once the news reports a real treasure find, Doraemon agrees to take him, Shizuka, Gian and Suneo sailing across the Pacific. A time distortion pulls their voyage back to the 16th century, a whirlpool wrecks their ship, and Nobita is swept away, washing up on an island with Jack, a boy separated from his family. The others are hauled aboard the pirate ship of Captain Kidd, where Jack's sister Betty is searching for her missing brother and father.