In the continent of Consume, Nintend-- I mean, Ninterudo Empire is in control of about 90% of the land, and SEG-- er, Segua Kingdom, is the last threat to their total domination. While Segua was getting all their biggest, baddest fighters together to stave off the impending ass-spanking by Mari-- er, Marcus, Sonic, I mean Gear, was living a peaceful life up in the mountains. That is, until Tails, I mean Til, dies horribly. So Gear decides to take revenge by joining Segua's army and fight.
Still with me, here? Add some ecchi shenanigans and copious amounts of video game character references, and you've got the fustercluck that is Aoi Sekai no Chuushin de.