High school student Kaname Sudou receives an invitation from a classmate to play Darwin's Game, a mobile game he has never heard of. However, as soon as he opens the application, a green snake suddenly pops out from his phone screen and bites his neck, leaving him unconscious. Waking up in the infirmary without any signs of a snake bite, he is told by the school to take the rest of the day off. Although he is puzzled by what has happened, he dismisses the surreal experience as a hallucination and boards the train home. Unfortunately, his curiosity gets the better of him and he uses the application once again. As the application appears to be just like any other battle game, Kaname breathes out a sigh of relief and decides to start his first match. However, the pleasant surprise is short-lived, as his in-game opponent unexpectedly appears right in front of him and attempts to hunt him down with a knife. As he desperately runs for his life, Kaname puts two and two together and realizes that Darwin's Game is not an ordinary game, but rather, it's a brutal fight for survival. [Written by MAL Rewrite]

On May 1, 1945 in Berlin, as the Red Army raises the Soviet flag over the Reichskanzlei, a group of Nazi officers conduct a ritual. For them, the slaughter in the city is nothing but the perfect ritual sacrifice in order to bring back the Order of the 13 Lances, a group of supermen whose coming would bring the world's destruction. Years later, no one knows if this group of officers succeeded, or whether they lived or died. Few know of their existence, and even those who knew began to pass away as the decades passed. Now in December in the present day in Suwahara City, Ren Fujii spends his days at the hospital. It has been two months since the incident that brought him to the hospital: a fight with his friend Shirou Yusa where they almost tried to kill each other. He tries to value what he has left to him, but every night he sees the same dream: a guillotine, murderers who hunt people, and the black clothed knights who pursue the murderers. He is desperate to return to his normal, everyday life, but even now he hears Shirou's words: "Everyone who remains in this city eventually loses their minds." (Source: ANN)

Far in the future, the lifeforms known as Gadoll suddenly arose as a threat to humanity. The last surviving humans on Earth confine themselves to the Tank, a lower district in the giant mobile fortress Deca-Dence. While the Gears who live on the upper floors are warriors who go out to fight as part of the Power, most Tankers are content to provide support from the backlines, butchering Gadoll meat and reinforcing defenses. Natsume is among those who would rather go to the front lines; undeterred by her prosthetic right arm, she seeks to join the small number of Tanker soldiers who join the Gears in combat. But despite her peers at the orphanage each receiving their work assignments, Natsume’s enlistment to the Power remains unapproved. In the meantime, she begins a job as a cleaner in an armor repair team led by the hard-nosed and apathetic Kaburagi, who seems to be more than he lets on. Though initially cold to his idealistic subordinate, he soon recognizes in her the potential to upset the status quo of the world. As Natsume’s new mentor, Kaburagi prepares her for the special and unique role as a game-changing bug in the system. [Written by MAL Rewrite]

A meteor strikes the Earth and is found to emanate a powerful new energy called Beamler, which is used to power a battle robot, GoShogun, and a teleporting fortress, Good Thunder. The Docougar Crime Syndicate, lead by crime lord Neo Neros, try to steal the secret of the energy from the inventor of GoShogun, but he kills himself rather than let them acquire it. His son is targeted by Neo Neros next, but he is taken in by the crew aboard Good Thunder, who travel the world fighting NeoNeros's forces with GoShogun. (Source: Wikipedia)