During their quest in the feudal era to recover the shards of the miraculous Shikon Jewel, Inuyasha, Kagome Higurashi, and their friends become the target of Menoumaru Hyouga—a demon awakened by one of the Shikon fragments, now in pursuit of Inuyasha's heirloom sword Tessaiga. Following a clash between the fathers of Inuyasha and Menoumaru, the weapon is the only means to restore Menoumaru his rightful family heritage. However, upon ambushing Inuyasha, Menoumaru discovers that Tessaiga's owner alone can wield it. Determined to achieve his objective regardless, he kidnaps Kagome to force Inuyasha to use his blade and release the sealed powers of the Hyouga clan. With their dependable companions' assistance, Inuyasha and Kagome oppose Menoumaru, unaware that his sinister intentions and alarming potential will endanger not only their world but also its distant future.

On a train to her new middle school, Momoka Sonokawa is preyed upon by a molester, only to be rescued by a girl wielding dual pistols. The girl turns out to be Miou Ootori, Momoka's upperclassman and president of the Aogiri Academy's Survival Game Club, called Sabage-bu for short. Noticing Momoka's aptitude with a pistol, Miou takes a liking to her and tries to persuade her to join the club. In spite of her steadfast refusal, Momoka inexplicably finds herself a member of Sabage-bu. Sabage-bu is anything but a typical middle-school club. Its members' socially awkward behaviors scare Momoka. Their personalities range from the fanatical to the completely delusional. They do not hold back from walking around public areas wearing ghillie suits or even bungee jumping from the school building. Thrown together with this collection of survival game maniacs, the zealously ordinary Momoka must somehow adjust to her unexpectedly wild school life.

On the outskirts of the country of Helvetia rests the tranquil town of Seize. Upon its cobbled streets, citizens go about their daily lives, undisturbed by the increasingly tense military relations between Helvetia and the neighboring Roman Empire. It is under these circumstances that the 1121st platoon of the Helvetian army, stationed at the Clocktower Fortress in Seize, receives a new recruit in the young and spirited Kanata Sorami. Having joined the military to fulfill her dream of learning to play the bugle, she excitedly accepts the tutelage of the Sergeant Major, Rio Kazumiya, who happens to be a skilled trumpeter. Working alongside them are the aloof mechanic, Noël Kannagi, the feisty gunner, Kureha Suminoya, and the compassionate Captain Felicia Heideman; together, they experience the beauty of life in Seize and the lasting joy of a community that has persevered in spite of the crumbling world around them.

Amagi Brilliant Park is a place where everyone takes on the role that is perfect for them. But every once in a while, situations arise that will force staff members to step out of their comfort zone and take on a new role. The goofball employees are soon to realize just how difficult this can be.