A.D. 2087 - the United Lunar Empire Giganos wages war on the Earth Federation Military to take control of the planet and establish a rebirth of the human race. During an invasion of a colony by Giganos' forces, three civilian men stumble upon a trio of top-secret Metal Armor units called Dragonars and pilot them to combat the enemy forces.

When the secret occult society, Shiromorishuua, sends a huge monster to attack Tokyo, ASY, a peace-keeping organization in Japan, retaliates with a Gousen (metal faery). ASY's Gousen annihilates the creature after driving it into open ocean. Although successful, a surprise attack follows. A girl, floating in midair and glowing with radiance, strikes with a beam of light. This girl is Rouran. She knows neither her identity, her origins, nor why whenever she senses the Gousen or Kyoushi (reanimated corpses) she transforms into an avenging angel. As Rouran worries about her mysterious existence, Tetsuya kindly watches over her in Tokyo Arcadia, a settlement of expatriates and dissidents. (Source: AniDB)

Twenty years into the future, a city now called Tokyo has developed into one of the few world-class high-tech centers, Tokyo City. The main character, Ken Kanzaki, is a young investigator assigned to the criminal investigation section of the Metropolital Police. He is one of the finest sharp shooters in the Police.One day, Ken is ordered to provide security for a party held by for Zaizen Konzern, a world-class plutocracy. All of a sudden, spector robots appear and distrupt the party. Zaizen, a commander-in-chief, is killed and both Ken and Jun. Zaizen's son,are fatally injured by the robots. Two of the party's guests, an auto-racer, Ryo Aguri,and a wresler, Go Goda, also receive serious injuries. Three severely injured young men are operated upon by scientists from the Metropolitan Police. Several days later, a robot corp led by a mysterious organization called Ido appears in the floating-town of the Tokyo Bay. But the Police and the Army have no effective strategies to contain them. At that moment, three young men attired in mechanical suits enter. They are the very three young men, Ken, Ryo and Go, who have been turned into the cyborg investigators through the operation. They call themselves Armored Police Metal Jacks. Metal Jacks, dazzlingly switching from Jack Suits to Jack Armors, completely demolish the robot corp and achieve victory, thus signals the beginning of the battle between the high-tech criminals and Metal Jacks with a futuristic Tokyo City in the background.

Zenitsu Agatsuma is determined to be the subject of adoration by receiving chocolates on Valentine’s Day—and this year, he is taking no chances. Enlisting the help of his friend Tanjirou Kamado, the two are prepared to learn from some of Kimetsu Academy's most popular figures. Together, they ask Kyoujurou Rengoku, the history teacher; Giyuu Tomioka, the PE teacher; and Tengen Uzui, the art teacher, about the secrets to their popularity. However, only time will tell if following their advice will bring the same success for Zenitsu.