In the middle of the 21st century, powerful individuals with superhuman strength appeared all across the world. These people who wore flashy clothes and performed incredible feats in the name of peace became known as heroes—symbolic figures of the nation they came from. In Japan, 14-year-old middle school student Teru Momijiyama is widely known by her secret identity as Japan's hero, Shy. As a young, timid girl, Shy is a fairly new hero with a lot to learn. She struggles with self-confidence and questions if she is worthy of the hero title. Even though she is unsure of herself, Shy works hard to save people and do the right thing. As new, powerful threats reveal themselves, Shy must cooperate with heroes around the world all while learning what it means to be a hero.

Following the revelations of the archangel Gabriel, Ente Isla hero Emilia Justina—who lives on Earth under the alias Emi Yusa—starts doubting the validity of her mission to slay the Demon Lord Satan, now reduced to a modest employee of MgRonald's as Sadao Maou. At the same time, Sadao's high school-aged coworker Chiho Sasaki pursues a new dream with hopes to protect not only herself but also her friends. Secretly training with Emi and Suzuno Kamazuki to develop telepathic powers, Chiho's training is cut short when a group of demons abducts her. As angel and demon attacks threaten the fragile peace between the two worlds, Sadao and Emi need to put their troubled past behind them if they want to have a chance to find their new purpose in life.

In 2242, the remnants of humanity are forced to live in scattered bubble-like cities across devastated lands. Hiding from toxic rain and hostile lifeforms known as Enders, they survive thanks to a new source of energy from AO crystals. Those tasked with risking their lives to collect AO crystals are called drifters, piloting versatile bipedal tanks with the support of combat androids named magus. While exploring remote ruins with his exceptionally gifted drifter friend Tokio, prospective drifter Kanata uncovers Noir, a seemingly intact magus in stasis. Although she wakes up by herself, Noir has lost her memories and is of no help in Kanata's work. However, amid an Enders attack, Kanata discovers that Noir possesses remarkable combat abilities. The pair now embarks on a journey to not only shed light on Noir's past but also to uncover the location of Histoire—the mythical city harboring secrets of the world that Kanata has always dreamt of visiting.

As a spirited young girl, Yohane ventured into the big city with ambitious dreams of becoming a star. Two years later, she has yet to pass a single audition. Since Yohane cannot support herself alone, her mother invites her back home to discover something new that only she can do. With limited options and an empty wallet, Yohane reluctantly returns to Numazu, her hometown. In the seaside town, Yohane reunites with her canine companion, Lailaps, and slowly settles in, opening a fortune-telling shop. She reconnects with old friends she had forgotten and meets new ones, all of whom help in her search for a unique purpose and meaningful path in life. Unfortunately, all is not well for Yohane and the people of Numazu: a mysterious power is affecting the town and disrupting nature and wildlife. While forging stronger bonds with her newfound allies, Yohane devotes her summer to finding the magic that may help save Numazu.