The world is in the midst of the industrial revolution when horrific creatures emerge from a mysterious virus, ripping through the flesh of humans to sate their never-ending appetite. The only way to kill these beings, known as "Kabane," is by destroying their steel-coated hearts. However, if bitten by one of these monsters, the victim is doomed to a fate worse than death, as the fallen rise once more to join the ranks of their fellow undead. Only the most fortified of civilizations have survived this turmoil, as is the case with the island of Hinomoto, where mankind has created a massive wall to protect themselves from the endless hordes of Kabane. The only way into these giant fortresses is via heavily-armored trains, which are serviced and built by young men such as Ikoma. Having created a deadly weapon that he believes will easily pierce through the hearts of Kabane, Ikoma eagerly awaits the day when he will be able to fight using his new invention. Little does he know, however, that his chance will come much sooner than he expected... [Written by MAL Rewrite]

In the eyes of the public, Fudou Aikawa and Desumi Magahara are sworn enemies who have nothing in common. Fudou, also known as "Red Gelato," is the leader of the hero squadron "Gelato 5," whose mission is to bring about world peace. On the other hand, Desumi is the minion leader of "Gecko," a villainous organization seeking world domination. However, despite these differences, their relationship is not quite what it seems. When they are not making a show of being at each other's throats, Desumi and Fudou continue to pursue a forbidden love. Going on dates, baking sweets for one another, and meeting up as often as they can despite their hectic schedules, the two inexperienced lovebirds pave the way for their own unique relationship. Though their public lives are worlds apart, Fudou and Desumi will stop at nothing to make their seemingly impossible romance work.

"Kings" are individuals who have been bestowed with incredible supernatural powers and granted the ability to recruit others into their clans. Protecting the lives and honor of their clansmen is an integral part of the Kings' duties. After a video depicting the heinous murder of a Red Clansman spreads virally, the unassuming student Yashiro Isana is accused of homicide. Now, a manhunt is underway for his head, bringing him into contact with the infamous "Black Dog" Kurou Yatogami—a skilled swordsman and martial artist determined to follow the wishes of his late master, the Seventh King. Meanwhile, the current Red King, Mikoto Suou, faces his own imminent demise as the search for Yashiro narrows. But during Yashiro's struggle to prove his innocence, a greater conspiracy is unraveling behind the scenes; clouds begin to appear in his memory, and close friends start to question his very existence. What began as a simple murder is now leading towards a full blown war between Kings with the very fate of the world at stake. [Written by MAL Rewrite]

One year after the events at the Sanctuary, Subaru Natsuki trains hard to better face future challenges. The peaceful days come to an end when Emilia receives an invitation to a meeting in the Watergate City of Priestella from none other than Anastasia Hoshin, one of her rivals in the royal selection. Considering the meeting's significance and the potential dangers Emilia could face, Subaru and his friends accompany her. However, as Subaru reconnects with old associates and companions in Priestella, new formidable foes emerge. Driven by fanatical motivations and engaging in ruthless methods to achieve their ambitions, the new enemy targets Emilia and threaten the very existence of the city. Rallying his allies, Subaru must give his all once more to stop their nefarious goals from becoming a concrete reality.