Choujigen Kakumei Anime: Dimension High School

Junpei picks up an unusual stone, only for it to begin speaking during a tutoring session. The encounter draws him, three fellow students, and their teacher into another dimension where their familiar school routines no longer apply.

A sphinxlike being confronts the group with a succession of riddles and challenges. Getting home depends on their ability to reason through the puzzles and cooperate under pressure. As the tests continue, the stone's intentions and the danger behind their predicament become increasingly difficult to ignore.