Deca-Dence

In the distant future, humans have been pushed to the verge of extinction by the invasion of mysterious life-forms called the Gadoll, and were now forced to live inside the moving fortress Deca-dence as they desperately kept up resistance. Natsume, a girl who grew up with a dream of becoming a fighter, is assigned to work under the hard-nosed but apathetic armor-repairman Kaburagi, and finds herself spending her days swamped with endless routines of cleaning work. But one day, Natsume gets herself caught up in a battle with the Gadoll while on work, and what she witnesses is the sight of Kaburagi taking down one Gadoll soldier after another.

As Kaburagi knocks down the Gadolls. with his tremendous strength and abilities, Natsume feels at a loss what to do as she finds herself in the battlefield for the first time in her life. Meanwhile, the true nature of the world that is hidden from humans like Natsume is revealed to the viewers...

Natsume learns how to fight against the Gadolls under the tutelage of Kaburagi. Though the training by the former top-notch warrior is harsh, Natsume perseveres, and her fighting skills & physical abilities improve dramatically in a short time.

Natsume heads into battle in an attempt to save Pipe, and the Tankers take notice. A potential for career advancement brings Kaburagi to a crossroads as a new event looms for Deca-dence.

The stage is set for a tragedy. Natsume sorties out alongside the Power, but the squadron does not stand a chance against a Cheat-level Gadoll. When all hope seems lost, Kaburagi appears.

Kaburagi has vanished, leaving Natsume to look after Pipe. What will happen to Kaburagi in the cyborg world, now that he has acted against the system?

Kaburagi uses his hard-won prize to return to Deca-dence. However, without his old account, he finds himself an outsider in his own life. With everything that's changed, Natsume and Kaburagi each come to a realization about their future.

Kaburagi convinces the other cyborgs to help him destroy the Gadoll factory. But can they find a way to do that while stuck inside a prison? Natsume sees a familiar face, while Minato comes to a crossroads.

The time has come for Kaburagi, Natsume, and the others to put their plans into action. Little do they know they've been betrayed. Can they stand against the system, despite the already slim odds of success?

Natsume learns the truth and sees her relationship with Kaburagi in a whole new light. The cyborgs need to escape the the correctional facility. How long can the bugs escape the system's clutches?

The new Gadoll crosses paths with Deca-dence, but the system underestimates its capabilities. Kaburagi is faced with an important decision, but will it mean losing his relationship with Minato?

It's a race against the clock to defeat Gadoll omega. However, even if Jill's plan to use Deca-dence as an avatar works, the fortress main weapon is in shambles. Will Kaburagi and Natsume find a way to defeat omega and save Deca-dence?