Death is one of many mysteries that has left humanity in the dark since the dawn of time. However, the burning question of what happens to the soul after one dies is soon answered to 17-year-old Yuzuru Otonashi. Waking up with no previous memories in a dimension between life and death, he discovers the unsettling truth of the afterlife. Taking the form of a high school, this bizarre dimension is designated to shelter those who died unwanted deaths. Feeling wronged by God during their earthly lives, the school's residents have decided to form the Afterlife Battlefront—a rebellious faction determined to oppose their god-like student council president, Kanade "Angel" Tachibana. The group's leader, Yuri Nakamura, recruits Otonashi in their fight against Angel in order to take control of their own lives. However, questioning the morality behind their actions, Otonashi takes a step behind the enemy lines to understand the opposing side of their common fate.

Private detective Sousuke Kaburaya is simply trying to make ends meet when Sara da Odin, an imperial princess from another world, falls through a portal right on top of him. Unaware that she is an anomaly in a magicless world, Sara uses powerful spells in public, causing a commotion and forcing Sousuke to take her back home with him. With the help of the internet, manga, and modern Japanese conveniences, Sara grows accustomed to living in Japan and becomes Sousuke's assistant in the process. Meanwhile, Livia de Udis, Sara's personal knight, also comes through the portal but lands at a different location. There, she meets a homeless man who readily accepts her unique background and odd tendencies. Despite her situation, Livia quickly adapts and settles into the homeless lifestyle, a far cry from the noble position she used to hold. While Sara and Livia may be living different lives, their positive and ambitious attitudes leave a lasting impact on the people around them as they experience both the good and bad of Japan.

After passing away, a Japanese office worker finds himself reincarnated in another world as Ars, the newborn son of the noble Louvent family. The Summerforth Empire, where the Louvents rule over a small territory of a few thousand people, is a medieval-like land plagued by social inequality and political instability. As Ars grows older and learns more and more about his new environment, he becomes convinced that war will soon erupt. Fortunately, though Ars was not blessed with unrivaled strength or extraordinary magical aptitude, he does possess Appraisal: a seemingly unique skill that allows him to instantly grasp someone's current abilities and latent talents merely by looking at them. In an effort to prepare his domain for the imminent strife, Ars resolves to enlist the most exceptional people he can find, paying no attention to superficial qualities like race or social status.

After the unexpected death of her father, 11-year-old Momo Miyaura leaves Tokyo with her mother and moves to an old remote island in Seto Inland Sea. The only memento she has from her father is an unfinished letter with only two words inside: "Dear Momo"—along with her heart's unrest from it. In the new and unfamiliar small town, Momo reluctantly tries to adjust to the outmoded wooden buildings, silent crop fields, and mysterious isolated shrines. One day, while exploring the attic of her new home, she finds a worn out picture book about youkai. Following this discovery, strange things begin to happen around town, and Momo is greeted by the arrival of three troublesome youkai. Momo e no Tegami tells the story of a young girl as she struggles to adapt to her bizarre new life and ultimately come to terms with her father's mysterious letter.