This is the kind of show that makes you hold your breath during a sleepover scene because you already know who's not making it to the next episode. Sheena's orphanage raises its girls as weapons first and children never, and the show never lets you forget that math even when it's giving you quiet, mundane moments between the bloodshed. The night her roommate dies and a stranger walks in grinning with someone else's blood on her skin, you feel the whiplash the show is built on, tenderness and horror sharing the same breath. What actually lands is the restraint, nobody here is a flat tragedy prop, every death costs something because the writing slowed down long enough to make you care first. Yeah, the slice-of-life stretches drag if you're impatient, but that's the price of a gut-punch that actually works. Slept on doesn't mean small, it means you haven't cried yet.

Sheena grows up in an orphanage designed to forge children into killers, a place where death is routine and mercy is a liability. But Sheena wants no part of this life. She dreams of peace in a world built for violence. On the night her roommate dies, she meets a bloodstained girl who smiles serenely while chaos surrounds them. The next day, that same girl enrolls in Sheena's class under the name Mimi, and rumors spread quickly: she's the facility's secret weapon, an immortal who cannot die. When Mimi becomes Sheena's assigned roommate, tension and attraction grow between them. Sheena, who longs to stop the killing, must now share her life with a girl who embraces death and seems untroubled by the war.