The green Verdies are the tiny, but brave guardians of the lakeside. The young Verdies only become guardians when their hair turns brown. Until then, however, life is boring. The youngsters with green hair are not allowed to fly on warblers, not allowed to row alone, and they're not allowed to ride wild frogs at the rodeo. Willy Whistle's big dream is to become a guardian, but his curiosity always gets him into trouble. However, the whole lake becomes at risk when the enemies of the lakeside, the Grimps and the swans, enter into alliance. The guardians are helpless, but Willy comes up with a daring plan in order to save his home and his trapped friend, Jeremiah Jump. Luckily he is not alone, because Grandpa, the water snakes and the frogs also come to his aid.
在一次偶然的情况下，大雄（小原乃梨子 配音）与多啦A梦（大山羡代 配音）穿过秘密通道时空圈，闯进一个森林中古代文明的国度——玛雅王国，他们遇上跟大雄长得一模一样的迪奥（绪方惠美 配音），迪奥是玛雅王国的王子。迪奥王子的母亲中了魔女娜汀拉（唐泽润 配音）的诅咒，长眠不醒。为了救母亲，迪奥王子一定要打败娜汀拉。因此在森林中修炼。迪奥王子从大雄口中得知现代日本的事，便对日本产生兴趣，所以迪奥便希望与大雄转换身份，到日本修炼。大雄便成为了王子；王子就成了大雄，各自展开不一样的生活，最后迪奥在日本认识了技安等人，他们一起去对抗娜汀拉，究竟他们能否打败娜汀拉救迪奥的母亲…… 本片是为了纪念哆啦A梦诞生30周年而制作的，是哆啦A梦电影系列第21部作品。
