In a near-future Japan, the concept of human rights has been reduced to a commodity. Citizens who can afford to keep their rights cards live within the bounds of protection and law, but those who lose their rights for any reason become known as mujina. With no legal identity or protection, these people exist in a societal void, unable to secure housing or employment through official channels. However, the same laws that refuse to protect them also cannot punish them, making the status of mujina a brutal form of freedom. For those with the necessary skills, this freedom can be weaponized, and mujina frequently find work as elite assassins for clients who need deniable killers.

The story centers on three individuals whose lives collide unexpectedly. Terumi Morgan is a disillusioned game developer who has accepted a life of quiet desperation, caring only about meeting his work deadlines and being left alone with his adult videos. After a bout of illness forces him to take a sick day, his mundane existence is shattered when he crosses paths with a runaway teenager named Juno Oshima and a thirty-year-old mujina assassin known as Ubume. Juno fled her hometown after suffering brutal abuse and neglect from bullies, her school, and even her own parents, hoping to earn enough money to hire a mujina to exact revenge on everyone who wronged her. Instead, she finds herself robbed of her possessions and nearly raped by a famous rock star before Ubume intervenes.

Ubume is a seasoned killer at a crossroads in her career. Highly skilled with an electrified katana and specialized boots called nakamatsu that enable superhuman rooftop acrobatics, she takes on assassination contracts to survive while secretly searching for a mysterious man in a tanuki costume, a figure from her past whose significance is slowly revealed through fragmented flashbacks. Her reputation comes under threat from Tenko, a younger, more vicious mujina who treats killing as a form of sexual arousal and develops a dangerous obsession with Ubume. Their violent confrontation leaves Ubume wounded and forces the unlikely trio of assassin, runaway, and office worker to take refuge together in Terumis apartment, forming a strange surrogate family bound by circumstance rather than choice.

The narrative unfolds across several notable arcs. The initial collision arc establishes the brutal world and brings the three main characters together after Tenkos attack. Subsequent arcs follow Ubume as she accepts various assassination contracts, each job revealing more about the corruption permeating this future society where elderly citizens over eighty-five are stripped of their rights and shipped to segregation zones called senior zones to die, and where corporations and wealthy individuals freely exploit mujina labor for their darkest needs. A significant arc focuses on Junos backstory, exploring the failures of child welfare systems and the cycle of abuse that drives teenagers to the streets, while also following her growing resolve and her complex relationship with Ubume, whom she both fears and admires. Another major storyline introduces Mai, a new mujina who injects a potent stimulant called Clean Boosters before her hits, representing a younger generation of even more reckless and desperate fighters. Ubumes ongoing search for the tanuki-suited figure from her past serves as a throughline, building toward confrontations that promise to reveal the full truth of how she became a mujina and what she has lost. The manga is structured in seasons, with the first season concluding as the characters face the escalating consequences of their actions in a society that has declared some lives worth protecting and others worth nothing at all.