The story begins 15 years after the demon king was defeated and the world has become peaceful. Kotone, who graduated from school and became a magician, inquired about the kingdom-affiliated RPG Real Estate in order to find a new home. In reality, RPG Real Estate was Kotone's place of employment, and together with Fa, a demi-human, the priest Rufuria, and the soldier Rakira, they help support the searches of new homes for the customers with various circumstances.

Kimizuka Kimihiko is a crisis-magnet. From getting caught up in a crime scene to accidentally witnessing a drug deal, trouble seems to find him around every corner. So it is no surprise when his rather mundane flight suddenly enters a state of emergency with a dire need of a detective onboard. Unfortunately, his attempt at avoiding trouble is foiled by a beautiful girl with silver hair who goes by the codename Siesta. Declaring herself a detective, she unceremoniously drags Kimizuka into the case as her assistant. That incident spelled the beginning of an adventure around the globe that went beyond his wildest imagination. Putting their lives on the line, the two took down criminal organizations, prevented disasters, and saved thousands. But the curtain closed to their epic journey with Siesta's untimely death three years later. Resolving to live an ordinary high school life this time, Kimizuka spends a year maintaining a low profile. However, as fate would have it, a girl with an uncanny resemblance to Siesta comes crashing into his life, threatening to throw his peaceful days into disarray. [Written by MAL Rewrite]

After the third world war, nations devastated by biological warfare no longer have the ability to protect the wastelands, so the defense of these territories is left to private military companies like Griffin & Kryuger, whose android soldiers or "tactical dolls" are tasked with fighting the rogue android army of Sangvis Ferri. Now M4A1, the indecisive but potentially capable leader of the elite "Anti-Rain" team must protect her comrades in a series of operations to try and regain the upper hand against Sangvis Ferri.