From MangaHelpers:

Kashima Lin comes from a family of people who can cause dolls to come to life and perform tasks. While she was away from Japan, both her older sister Shiori and her grandfather died in a mysterious fire. She returns to Japan, convinced that Shiori's fiance, the famous violinist Serikawa Akito, murdered them and stole their family's special dolls.

Now Lin, with the help of her childhood friend Tomoe, is determined to do whatever it takes to make her sister and grandfather's murderer pay and to take back what is rightfully hers. [tethysdust]