Junichi Nagase was a real delinquent in middle school, one nasty enough that he earned the nickame "Geno Killer," and it's by this less than flattering epithet that Yuuhi Katagiri first comes to know him when he rescues her from two thugs one evening. Needless to say, both are stunned when not only does Yuuhi find herself transferred into the same high school class as "the Killer," but that shock grows into outright stupefaction when Yuuhi shows up at Junichi's house with the mind-blowing announcement that she's supposed to move in with him! It seems that they're engaged, and since this is the first that Junichi and his younger sister Minato have first heard of the arranged marriage set up by their parents, it's an idea that's going to take a little getting used to. Get ready for ties that bind and gag as bad boy and good girl collide cohabitationally while the entire school gets to watch!

Operating out of his private anthill, the formidable Atom Ant picks up distress calls via his built-in antennae and heads out to battle a fearsomely delightful array of dastards including Bug Fat Dynamo, Crankenshaft, M.D. and his arch-nemesis Ferocious Flea. Sharing screen time with our hero are Precious Pupp, a rascal of a mutt who hides his antics from the kindly Granny Sweets and the Hillbilly Bears, the most ridiculous bears to ever come from the Blue Ridge Mountains.