Mimitsuki

One day then your typical good-for-nothing high-school student - Shizumori Shimataro - was brought to family meeting by his brother and sister in "no time to explain get into the car" manner, he learns two things which will change his life. First is the reason of why all his relatives have extremely good sense for things. And second what he is now in charge of recently dead uncle's antique store. When Shima get the girl? Well, right after his brother says him what it is most difficult family duty he just inherited.