A girl raised to be a weapon meets someone who smiles at the end of the world, and suddenly her only want becomes keeping that person alive. The romance isn't a subplot that makes the darkness bearable, it's the thing that makes the darkness matter, the reason every death costs something. Sheena's love becomes an act of defiance in a place built to strip defiance away.
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. Everything changes when a bloodstained girl appears during the orphanage's darkest hour, smiling serenely while chaos erupts around 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 ultimate secret, an immortal warrior who cannot die. When Mimi becomes Sheena's assigned roommate, their connection deepens into something neither expected. As Sheena discovers more about Mimi's impossible nature and tragic past, she finds herself drawn to someone who has watched centuries pass while remaining untouched by time's weight. In a place built to destroy love, these two girls begin to ask if happiness is possible for weapons like them.