Yuzuru Shiga lives an ordinary life, spending most of his time with his high school archery team along with his girlfriend, Satomi. His relatively mundane life gets complicated, however, when his aunt dies under suspicious circumstances and his cousin and fiancée, Azusa, re-enters his life. While Yuzuru sees her as a mere relative, she is dangerously serious about their future marriage and will not tolerate the threat of Satomi. As things continue to get ever stranger since Azusa's return, Yuzuru now has to decide whether his relationship with Satomi is worth the potential danger.

Legend says that centuries ago, a colossal spider ravaged Tokyo. Resistance was futile, as none could quell the havoc wrought upon the city by the beast. Fortunately, one man—the legendary exorcist—stopped the devastation. Using his divine powers, he sealed the monster away and the world has enjoyed peace ever since. Mizuki Henmi is an adolescent girl who is acquainted with Shu Suzuri, a dull young man who runs an old Japanese bookstore. During a routine visit to his store, Mizuki learns of a mysterious and valuable book that Shu is planning to sell. Unfortunately, the unrestrained Mizuki handles the book roughly, breaking the seal that kept it shut and revealing an odd entity—a cute spider. Wasurenagumo tells the story of Mizuki, Shu, and their seemingly harmless spider. However, ominous winds begin blowing. While Shu is infatuated with his arachnid friend, Mizuki becomes wary of its every move…

In the magical academic city of Ashram, girls known as Pentagrams study general education, magic, and etiquette to become proper ladies. Hidden from the rest of the world, the school is like a secret garden that is home to blossoming flowers. However, bugs sensitive to magic may target and trample them; as one of their tasks, the girls must exterminate these insects. The smileless Pentagram Arsnotoria lives in the fifth dorm house alongside her adored roommates: the cheerful Mell, the self-paced Little Alberta, the confident Picatrix, and the cool Abramelin. No matter what time of day, they hang out together as much as possible, and even throw tea parties in their secret room after completing their duties. The girls live in peace as they work toward their goal—but there may be more to Ashram and the Pentagrams beyond the calm life they have come to cherish.

College student Miyako Hoshino is quite shy around other people. She mostly spends her time in her room making cosplay outfits. When her fifth-grade sister Hinata brings her classmate Hana Shirosaki home, Miyako instantly becomes captivated with Hana's cuteness. Miyako tries to do various things, ranging from making Hana wear cosplay dresses to giving her sweets. This gives Hana a bad impression of her at first, but Miyako will do anything to grow closer to the angel who has descended before her.