Sasasa Nana no Kyūmei

The manga centers on college student Sasasa Ruru and her sister and mystery novelist Sasasa Nana. Both sisters suffered a recent loss in the family: an uncle that passed away a month ago. When Ruru takes this as an opportunity to visit their uncle's old home, she discovers an old picture of Avi, her uncle's old partner who disappeared long ago. This begins to uncover some memories in Ruru's mind.