Naota Nanadaba is just an ordinary boy, with an ordinary life, with ordinary people around him, living in an ordinary town... or at least he wishes that were all true! Between his eccentric father and unconventional grandfather and putting up with the advances of his older brother's teenage ex-girlfriend Mamimi, Naota isn't leading a boring life at all! To make matters worse, a pink-haired, and apparently totally insane, girl named Haruko Haruhara shows up and turns Naota's life completely upside down!! What does Haruko want from Naota? And, why is he suddenly growing a large horn on his head?!