In the year 2027, the video game Phantasy Star Online 2 is all the rage at Seiga Academy. Every student is on board the fad—except for Itsuki Tachibana, a well-rounded student who doesn't play video games. Due to its popularity, the game is currently under review at Seiga Academy to see if it has a negative impact on the students. Consequently, this causes Itsuki to catch the attention of Rina Izumi, the perfectionist student council president who aims to prove that the game is not to blame. To accomplish her objective, Rina recruits Itsuki as the student council vice president and tasks him with learning to play the game while keeping his grades up. Now obliged to report his daily findings of the game to Rina and analyze its merits, Itsuki carries the fate of Phantasy Star Online 2 in his hands.

After centuries of antagonism and misunderstanding, the Japanese finally welcome youkai into their community. In an attempt at species integration, normal children begin attending school with paranormal creatures who are quite humanoid. Shingo Ohashi finds himself developing feelings for Hatoko Petoko Fujimura, a half-youkai half-human girl whose powers are: uncontrollable cuteness to enchant those around her (similar to a low-power succubus), get stuck to any other person who touches her bare flesh (cured by her falling asleep), and the ability to disappear even at the molecular stage (which she can for the most part control). (Source: The Anime Encyclopedia)

Kaito Daimon would be a completely average high school student except for one thing: he's a demon at solving puzzles. Kaito is so brilliant, in fact, that when he's asked to take some 'special' tests of his unique ability, he immediately suspects that the test itself is a test. Kaito suddenly finds himself caught up in a lethal Philosopher's Puzzle made by the sinister group POG, a murderous maze of trap upon trap, where failing to solve the secret correctly will result in death! Fortunately, Kaito's skills prove up to the first test, both for himself and his childhood friend Nanoha, who is also caught up in the deadly scheme. But now that he has been designated as a Solver, he is pulled into a new life where he must travel the world with other Solvers, attempting to solve the latest deadly riddles left by POG. There's a new conundrum around every corner and each deception could lead to death, but once a riddle has been posed, you can count on Kaito to unfold, unravel and unlock it! (Source: Sentai Filmworks)

Despite endless research, the human mind remains a mystery to this day. Unknown to the public, there exist special individuals who are able to dive deep into the minds of people and even manipulate their memories. Gifted with this ability, Hiroki, Tsukasa, and Satoru are among those who use their power to commit crime under the orders of their leader, Katsuragi. The three step into the dangerous territory of the human mind in order to destroy their assigned targets while striving to keep their own minds and memories safe.