When the Fourth Hokage fell, his personal guard detail went their separate ways. Most of the village knows where Genma, Raido, and Iwashi ended up, but the fourth member of their old squad disappeared into Konoha’s Black Ops without a trace. Now operating strictly from the dark under the codename "Fox," she has become an ANBU legend—a strategic genius who calculates circles around the Nara clan and executes the Flying Thunder God completely solo, moving even faster than the Yellow Flash himself. With Tsunade Senju officially taking over as the Fifth Hokage, the administrative backlog isn't the only thing on her plate. Tsunade loves a good mystery, and a high-ranking ANBU with midnight-black hair, an untouchable track record, and a completely hidden identity is a challenge she can't resist. As Tsunade turns the village upside down trying to unmask her, Fox relies on her elite training—and her old squad's tight lips—to stay one step ahead of the new Hokage's games.