Every 40 years, there will be a Gathering of Human Kids, whom will take part in an mysterious Game "Bakegyamon", created by the Hell Master. There is a rumour... when the final winner emerges, the child will receive a wish.

Because of that Rumour, lots of Active Kids, will like to start an Expedition! What will happen to them, in this mysterious game?
 

在一个被称作『逆JAPAN』的空间，每隔44年就会打开一次“妖逆门”释放大量妖怪，一位神秘的少年多闻三志郎将在这里展开异想天开的奇异冒险。