Ruth discovers a Hello Kitty lunchbox washed up on the shore of her Canadian beach home and suspects it might be debris from the 2011 tsunami. Within it lies a diary that expresses the hopes and dreams of a young girl. With every turn of the page, Ruth is sucked deeper into an enchanting mystery, in which 16-year-old Nao Yasutani is trying to find a reader and friend who finally understands her.