Menou exists to kill people like the ones every isekai protagonist befriends, and the show's entire premise is watching her job description collapse the moment she meets someone worth saving. It builds a world where Japan is the alien threat, where the power to come back from death is a curse, not a cheat code. By the time you realize this isn't about executing Lost Ones, it's about Menou executing her own purpose, the emotional weight has already shifted everything.

Menou is an executioner tasked with hunting down Lost Ones, interdimensional travelers from Japan who arrive in her world carrying catastrophe in their wake. She's efficient, cold, and unquestioningly committed to eliminating threats before they spiral into chaos. Her latest assignment seems straightforward until she corners a Lost One named Akari and discovers something impossible: this girl refuses to stay dead. What begins as a simple execution becomes complicated. Menou sets out to find a way past Akari's immortality, and Akari cheerfully comes along for the ride. Menou intends to finish the job no matter what, as long as the feelings starting to stir in her don't get in the way. The action fantasy drama is adapted from a light novel series.