Touta Konoe is an ordinary boy raised in a small rural town. His mundane life suddenly changes when his mentor, Yukihime, reveals herself to be a vampire; after saving Touta from a mortal wound, she causes him to become immortal as well. Already yearning to explore the world, young Touta finally puts his dream to ascend to the top of Amanomihashira—a tower that leads to outer space—into realization. Along the way, he finds a secret society filled with immortals just like him called UQ Holders. Gaining new comrades and mentorship along the way, Touta embarks on his own unique, magical adventure.

Despite their differences in position, three men—the youngest senior executive of the Port Mafia, Osamu Dazai; the lowest ranking member, Sakunosuke Oda; and the intelligence agent, Ango Sakaguchi—gather at the Lupin Bar at the end of the day to relax and take delight in the company of friends. However, one night, Ango disappears. A photograph taken at the bar is all that is left of the three together. Fast forward to the present, and Dazai is now a member of the Armed Detective Agency. The Guild, an American gifted organization, has entered the fray and is intent on taking the Agency's work permit. They must now divide their attention between the two groups, the Guild and the Port Mafia, who oppose their very existence.

For weeks, Atsushi Nakajima's orphanage has been plagued by a mystical tiger that only he seems to be unaware of. Suspected to be behind the strange incidents, the 18-year-old is abruptly kicked out of the orphanage and left hungry, homeless, and wandering through the city. While starving on a riverbank, Atsushi saves a rather eccentric man named Osamu Dazai from drowning. Whimsical suicide enthusiast and supernatural detective, Dazai has been investigating the same tiger that has been terrorizing the boy. Together with Dazai's partner Doppo Kunikida, they solve the mystery, but its resolution leaves Atsushi in a tight spot. As various odd events take place, Atsushi is coerced into joining their firm of supernatural investigators, taking on unusual cases the police cannot handle, alongside his numerous enigmatic co-workers.

Death does not have to be the end; one can live again, but only through beating the game posed by the black ball called Gantz. On his way home to celebrate his younger brother's birthday, brave and kind-hearted student named Masaru Katou is stabbed to death. He awakes in a small room with a cityscape view in the heart of Tokyo—and he is not alone. To his surprise, it is not the afterlife, but the waiting room for a high stakes game with their lives on the line. Before he has the chance to process the situation, Masaru is handed a gun and teleported into the center of Osaka to carry out one simple task: eliminate any alien on sight. Accompanied by the aged Yoshikazu Suzuki, the stunning idol Reika Shimohira, and the cold but experienced Jouichirou Nishi, Masaru must overcome his fears in order to survive the game and return home to his waiting brother.