The Noharas win a free vacation to the Buri Buri Kingdom, but in mid-air the White Snake gang seizes their plane: they are after Shinnosuke because he looks exactly like the kingdom's kidnapped Prince Sunnokeshi. With the prince already in the gang's hands and the royal treasure sealed behind a lock only the two boys can open, Shinnosuke's family and the prince's bodyguard Ruru race to reach the vault first.