At the end of Fifth Holy Grail war, the unknown dark magic invaded the Heroic Realm. As the cause, several Heroic Spirit is corrupted, and causing chaos in the Realm. The Holy Grail, desperate to save itself and the Realm, summon seven persons into the Heroic Realm itself. A full-scale war between the Heroes is about to begin, and only these people can save humanity and the realm.

A story of Gudako , a new master that desperately trying for a golden, no , a super rare servants from the summoning gate. Someday , Gudako success summon a super rare servant , nero. Just a day after getting nero , she fell out into a dimensional hole and forced to take on a holy grail war , with nero as her servant.