This is not a regular gender bender story, is in fact a bold and extraordinary manga. That is the reason why it is a masterpiece, but also why it is so disliked by many. Inside Mari is a story about a hikkikomori who switch sides with the girl he adores, and so suddenly sees himself on difficult situation having to live on as the girl he worships. Although, it is a simple and overused premise, it goes beyond by exploring this genre from a more psychological approach and by doing it with absolute finesse. It's a worth looking bizarre masterpiece.