Hiroshi and Misae have never been to a honeymoon trip to a foreign country. One day, Misae discovered an inexpensive and family-friendly holiday package to Australia and the Nohara family decided to make it their first honeymoon vacation.

Hiroshi gets kidnapped upon arrival to Australia, leaving Shinnosuke, Misae and others on a dangerous journey. It turns out that Hiroshi is the key to a secret treasure. The remaining members of the Nohara Family must rescue Hiroshi, while a mysterious masked man and treasure hunters from all over the world are after him. The struggle is among three different groups in this action-filled treasure hunting adventure.