Zephyr and Frisounet are on holiday on a cruise. On the day of the excursion, they rescue a baby sea monster stuck in a net. To thank them, he takes them to Scotland to meet the Loch Ness monster, who plays water slides. From there, they visit a haunted castle where they are thrown into an enchanted forest. Then they visit the center of the Earth and the Underworld, and emerge in Japan, populated by hundreds of yokai. They then cross paths with dragons before entering Aladdin's magic lamp...