Mai finds a hidden map that brings her to another world. With some newfound friends, Mai sets off to hunt for the legendary treasure! But with rivals in her way, will she finally get her hands on the legendary treasure...?

Leonard Poire, the famous treasure hunter, died years ago. Most of the treasures he found were since plundered by bandits, but he left behind a series of riddles about a legendary treasure that only a hunter as great as him will be able to find.

Mai, a seemingly ordinary girl, has always dreamed of visiting another world filled with treasure and adventure. When she finally finds her way to one, she discovers the people there are just like her: obsessed with treasure! It's a world full of treasure hunters and bandits alike.

She wanted to explore this new world with her good friend Kenichi, but instead, their enemy Takuya comes with her. Even worse, he's gained mysterious powers in the process of coming to the new world and joined forces with its evil inhabitants.

The world's filled with people of magical species, from yetis to divinities, all of whom may pose a threat to Mai on her journey. Will Mai make her dreams come true, or will she stumble before the legion of foes who oppose her? Defeat all comers and solve the riddles along the way to find the legendary treasure!