Based on the game by ELF.

The once peaceful city-state of Lisvalletta has found itself beset by a dangerous new drug called Anthem. The side effects of the drug allow the user to enter a state of Overdrive, wherein they mutate into superpowered beasts with inhuman abilities. With the police powerless to stop this new threat, the responsibility falls upon the Special Crime Investigation Unit SEVEN-O. To offset the dangers of this work, the investigators work under the patented Double Decker system, which requires them to team up in buddy cop pairs. As a child, average police officer Kirill Vrubel fantasized about being a hero who would save his school from a random terrorist attack. His chance to be a hero arrives when his landlady blackmails him into searching for her lost cat. Upon arriving and falling asleep in an abandoned warehouse, Kirill finds himself in the middle of a hostage situation involving an Anthem user. By teaming up with SEVEN-O detective Douglas Doug Bilingam, Kirill earns his spot as the newest member of SEVEN-O. Now, with the help of this secret organization, he may finally achieve his dream of becoming a hero.

Xiao Yan, the best Xiao family fighter ever. At the age of 4, he began his training, at 10 he already owned the ninth level of strength, and at 11 - the tenth, so he became the youngest fighter in the history of his family. But at the age of 12, something unpredictable happened: he lost almost all of his strength. For the next three years, neighbors mocked him and even broke off his engagement. It would seem that nothing will help him, but then a spirit appeared from his ring, which showed him the way to power. Xiao Yan again became a favorite of the family and the crowd, but this could not satisfy his ambition. To avenge the failed wedding, he goes to the mountains and, with the help of an old herbalist, becomes stronger and stronger.

In a school where after school activities are mandatory among all students, Hajime and her friend Sayo come across a new club that they have never seen before. The club is called The Cultural Activity Preservation Club. The two enter the room to find all kinds of analog jobs and activities, such as handcrafting mats and toothpicks. This is a unique cultural anime mixed with comedy so as not to bore you, this is Double J! (Source: Mangahelpers, edited)