Bad ending is that Miki refuses to tell the parents. Kazuki’s not all to happy about it cuz he hates having to be all secretive, but if his darling sister says so, oh wellz. Couple of years later, Miki’s become an OL and Kazuki’s still at school. Their relationship is still kept secret and Kazuki’s just badgering Miki to get an apartment so the two can live together.