In Edo in the mid-1800's, fireworks maker Seikichi Tamaya and his friends struggle to live under the harsh morality laws imposed by the strict city councilor, which ban all luxuries, including fireworks. One day, a strange girl stops by Sekichi's shop with an equally strange request: she wants Sekichi to build a firework that can reach the moon.

The story takes place between the first and second season, where Rimuru confronts the swirling conspiracies in the Coleus kingdom.

After battle in first season battleship Amanohara was serious damaged and need to repair. It land on island where a Gogyou festival just begin. Umakai Shintaro and his five girls student who know as Raimu Unit begin enjoy a peace time in that island. But the enemy still follow them around. How Umakai Shintaro and his five girls student fight against the enemy. Still his five girls student begin try to draw his attention into them.

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 infatued with his arachnid friend, Mizuki becomes wary of its every move…