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.

In an unexpected turn of events, dull high school student Hiro Yuuki obtains the full dive role-playing game Kiwame Quest. Created by the best of technology, the game claims to take "reality to its extremes," from stunning graphics, NPCs' behavior, to the scent of vegetation, and even the sensation of wind brushing against the skin—everything was the result of an ultimate workmanship. Except, the game is a little too realistic and messy to clear. Kiwame Quest features over ten quadrillion flags and reflects the players' real-life physical abilities in the game. Being hit in the game also hurts in real life and slash wounds take days to heal. The only reward here is the sense of accomplishment. Conquer the most stressful game in history that can't be played casually!

Fuutarou Uesugi is a poor, antisocial ace student who one day meets the rich transfer student Itsuki Nakano. They argue but when Uesugi realizes he is to be her tutor, he tries to get on better terms. While trying to do so he meets four other girls.

A video game whiz helps create a new technology that enables players to guide their online avatars with their own bodies -- but a dark twist emerges.

Thirty years ago a strange phenomenon called a "spacequake" devastated the center of Eurasia, claiming the lives of at least 150 million people. Since then, smaller spacequakes plague the world on an irregular basis. Shido Itsuka, a seemingly ordinary high schooler comes across a mysterious girl at the ground zero of a spacequake and learns she is one of the "Spirits" who are the real cause of the spacequakes that occur when they manifest themselves in the world. He is recruited to make use of his mysterious ability to seal the Spirits' powers thus stopping them from being a threat to mankind. However, there is a catch: to seal a Spirit's power, he must make her fall in love with him and kiss him.

High roller Yumeko Jabami plans to clean house at Hyakkaou Private Academy, a school where students are evaluated solely on their gambling skills.