Dr. Cinnamon was living peacefully with his three great-grandchildren in Donburi Island. One day, he asked the youngest to go on an errand by piloting the GwinBee aircraft. However, he never came back... The doctor was starting to get worried, when suddenly a loud voice resounded throughout the laboratory and said: "GwinBee is in my custody. My name is the Demon King Poko Poko". Quickly, he ordered his remaining two great-grandchildren to board the TwinBee and WinBee fighting airships and bring him back. And so, both courageous pilots set off on a journey to rescue GwinBee.