The world know the story of the Cardinal Heroes. But, what if there is an addition? Meet Kanade Otonashi, a 18 years old girl who has been killed by her own best friend. However, instead of going into afterlife, she was sent to another world as the Katana Hero. Being a Hero who can join other Hero's party, she decided to make her own team. Now, she must protect this new world from a disaster known as the Wave of Catasthrope.

Kuroba Raiden has a sad life. A memories of his dead best friends make him suffer a lot. During his visit on his best friends' grave, he got dragged into the Arc-V world as reincarnation of Mizael from Yu-Gi-Oh! Zexal. Has been chosen by Galaxy-Eyes, he need to save the world from Academia and Z-ARC.