A girl wakes up from a coma and immediately makes a deal with an alien that might kill her anyway. The show never explains why that's the right choice, because it isn't one, it's just the only move left. Every episode pulls the camera back to show you how many other people made the exact same impossible decision, and what it cost them to live with it.
Azumi wakes from years of illness to discover a world transformed. Interdimensional rifts tore open long ago, bringing otherworldly beings called Z/X into our reality. Most nations maintain fragile truces with these creatures, but peace remains conditional and temporary. When a pact with Rigel, a striking Z/X warrior, offers Azumi her only chance at survival, she accepts without hesitation. The cost of her recovery is relocation to Xinfera Academy, where human students and their Z/X partners train together in secret. The school's true purpose becomes obvious the moment Azumi arrives: they're not just learning cooperation. They're preparing for the next invasion. Hostile forces from the dimensional rifts don't honor treaties. They're coming back, and they're coming harder. Azumi finds herself thrust into a conflict she barely understands, surrounded by new allies whose bonds with their Z/X partners run deeper than any contract. Between learning to trust Rigel and discovering what her dormant abilities mean for the coming war, Azumi must choose between the safety of her new life and the survival of both worlds.