Light of the River

Kawa no Hikari (川の光, lit. "Light of the River") is a 2007 Japanese children's adventure novel written by Hisaki Matsuura and featuring illustrations by Kazuko Shimazu. It was originally serialized in the newspaper Yomiuri Shimbun between July 25, 2006 and April 23, 2007, before being released in bound format by publisher Chuokoron-Shinsha exactly one year after its periodical debut. The book was later adapted into an animated TV special by Studio Gallop, which aired on NHK General TV on June 20, 2009 as part of the network's "Save the Future" lineup.

Plot
A family of three rats, brothers Tata and Chichi, and their father, referred to only as "Dad", live in a tree trunk beside a river just outside Tokyo, just as their ancestors had for generations. However, sudden construction work by humans causes their home to be blocked off, forcing them to search for a new place to live upstream. Time becomes a factor as winter is fast approaching, leading the trio to venture in and around the dangerous city, encountering allies and enemies of all shapes and sizes.