Konone is a warrior from a dying realm, a world where the "Heart Cards" represent the very essence of existence. When her home is consumed by the Void King, she escapes to Earth with a desperate mission: recover the scattered cards before the silence claims every world in the multiverse. She is a soldier of fire, disciplined and fierce, believing that only strength can win the day.

Enter Yui—a clumsy, perpetually optimistic high school student whose greatest challenge used to be passing math and helping out at her parents' restaurant. But when she accidentally bonds with a mysterious blue light, she becomes the unlikely anchor for Konone’s mission.

Together, they must lead a team of "Blazing Girls" to defend their city from the Shadow-Beasts. But as the battle reaches its peak, the cost of victory becomes a debt that only one of them can pay.