In the aftermath of a great and terrible war, Haruka finds herself the last surviving human on Earth. Though humanity may have been wiped out, she is not entirely alone. Advanced robots have survived the apocalypse, and Haruka lives with five who care for her: Spike, a boyish android who is very attached to her; Trigger, hot-tempered with a penchant for firearms; Cleric, the intelligent problem solver; Reeves, whose thoughtfulness overshadows his intimidating appearance; and Angela, a sword wielding recluse with an aversion towards humans. Residing in a high-rise building at the center of the city, Haruka lives a relatively peaceful life with her mechanical family. However, her life is far from a stable one. Not only is a lack of resources a concern, but violent, remnant robots from the war roam free, ready to destroy whomever they meet. Kurogane Communication follows Haruka as she tries to survive in an apocalyptic world while facing many dangers that will challenge her daily life.

In the year 2010, practically one hundred percent of Cat Earth's GDP comes from the megacorporation Catty & Co., which is rapidly spreading across the rest of the galaxy. Here lives Tamala, a beautiful yet foul-mouthed cat, who decides to travel to the planet of her birth, Orion. After an unfortunate crash landing on the planet Q, Tamala meets Michaelangelo, a fellow cat, whom Tamala refers to as "MoiMoi." As Tamala and Michaelangelo explore the planet's capital, Hate City—which is under martial law to separate the feuding cat and dog populations—they pass by graffiti and museum exhibits about the ancient cult of Minerva that speak of something dark and sinister. After Tamala catches the eye of the extremely violent motorcycle-riding Kentauros, she and Michaelangelo flee, but mysteries about Tamala's identity continue to surface. Why did Tamala originally leave Orion, and what exactly is her connection to Catty & Co.?

Mew and Mica are alien androids sent by their boss to defend the Earth. Unfortunately for our planet, they are the laziest superheroines you will ever meet. Now most superheroes would drop whatever they're doing, transform, and proceed to kick monsters' butts... but these two would do no such thing. Mew and Mica just can't let their duties interfere with their ice cream, arguments, or whatever activities they happen to be engaged in at the time. When they are not Hyper Dolls they seem to be just ordinary, rather cute school girls, lusted after by the boys.

Sasahara Natsuki is a poor bounty hunter in a world where monsters and humans live together. Most of her cases involve monsters infringing upon the rights of humans, who are protected by law from their generally more powerful neighbors. Being half-human and half cat-beast, Natsuki straddles the two societies and tries to understand and respect both while enforcing the law. She is assisted by a werewolf named Batanen who is afraid to admit he loves her; another werewolf named Tommy; and a Kyubi fox demon named Sakura who has her own plans--which include eating Natsuki to complete her her nine tails and thereby her magical powers.