Here is an overview of the game, via its Steam page:
Welcome to the beautiful world of Ni no Kuni!
After being overthrown in a coup, the young king Evan sets out on an extraordinary quest to found a new kingdom, unite his world and protect its inhabitants from the dark forces that threaten them.
Join him on an unforgettable adventure which blurs the line between animated feature film and video game. Developed by Level-5, Ni no Kuni II features enchanting character designs from the legendary artist Yoshiyuki Momose and a stirring soundtrack composed by the world-famous Joe Hisaishi.