Summary and Preview
After spending the first 10 years of her life searching for treasure with her father, Mahiru is finding it hard to adjust to life in Japan. It's been 5 years since her father's disappearance, but Mahiru still does crazy things, like eating live frogs or beating up classmates, to cope with how tedious her daily life has become.
All that changes when Mahiru meets Kaori, an otaku heiress who has found a heart-shaped artifact that is harder than diamond. Now Mahiru, her little brother, Kaori, and her butler are off to discover the origin of the heart-shaped artifact! [tethysdust]
-- from Official Site