A world where it has been established that people routinely swing between slightly different parallel worlds... Koyomi Takasaki, who lives with his mother following his parents' divorce, enrolls in a local university prep school. Due to the atmosphere concentrated on studies and his social awkwardness, Koyomi is unable to make friends. One day, he is suddenly approached by his classmate Kazune Takigawa, who tells him that she has travelled from the 85th world where she and Koyomi are lovers.

A large scale catastrophe is occurring across the planet. Ability users are discovered after the appearance of a mysterious fog, apparently having committed suicide, so the Armed Detective Agency sets out to investigate these mysterious deaths. The case seems to involve an unknown ability user referred to as "Collector," a man who could be the mastermind behind the incident.

Trust and courage are put to the test in order to save the city of Yokohama and ability users across the world from the grip of Collector where the Armed Detective Agency forms an unlikely partnership with the dangerous Port Mafia. 

[Written by MAL Rewrite]

Saenome are tasked with sealing spirits that possess objects and pose a threat to society. Known as tsukumogami, these spirits are generally non-violent, and saenome normally seal them after a simple verbal exchange. Traumatized by a previous deadly encounter with a malevolent spirit, Hyouma Kunato refuses to use peaceful methods and gets into physical confrontations with all tsukumogami that cross paths with him. Deeming this behavior unacceptable for a future clan leader, Hyouma's grandfather, Zouhei, proposes that he starts living with Botan Nagatsuki, a young woman whose family is composed of six tsukumogami—lest he be excommunicated. Determined to track down the spirit that took everything from him, Hyouma reluctantly accepts Zouhei's proposal. As unknown groups of evil spirits begin to jeopardize the balance between worlds, the young man must gain the trust of Botan and overcome his hatred for her mysterious family.

Clad in desert pink and the size of a mere child, the infamous "Pink Devil" mercilessly hunts down other players in the firearm-centered world of the virtual reality game Gun Gale Online. But in real life, this feared player killer is not quite who anyone would expect. A shy university student in Tokyo, Karen Kohiruimaki stands in stark contrast to her in-game avatar—in fact, she happens to stand above everyone else too, much to her dismay. Towering above all the people around her, Karen's insecurities over her height reach the point where she turns to the virtual world for an escape. Starting game after game in hopes of manifesting as a cute, short character, she finally obtains her ideal self in the world of Gun Gale Online. Overjoyed by her new persona, she pours her time into the game as LLENN, garnering her reputation as the legendary player killer. However, when one of LLENN's targets gets the best of her, she ends up meeting Pitohui, a skilled yet eccentric woman. Quickly becoming friends with Karen, Pitohui insists that LLENN participates in Squad Jam, a battle royale that pits teams against one another, fighting until only one remains. Thrust into the heated competition, LLENN must fight with all her wit and will if she hopes to shoot her way to the top.