A Tale for the Time Being

In Tokyo, sixteen-year-old Nao has decided there's only one escape from her aching loneliness and her classmates' bullying. But before she ends it all, she plans to document the life of her great-grandmother, a Buddhist nun who's lived more than a century. A diary is Nao's only solace. Across the Pacific a novelist living on a remote island discovers artifacts washed ashore in a Hello Kitty lunchbox and is pulled into Nao's drama and her unknown fate. (Bestseller)

Synopsis from Open Library.