 Doraemon is sent back in time by a young boy named Sewashi Nobi to improve the circumstances of his great great grandfather, Nobita, so that his descendants may enjoy a better future.In the original timeline, Nobita experienced nothing but misery and misfortune manifested in the form of very poor grades and bullying throughout his life.This culminates in the burning down of a future business he sets up which leaves his family line beset with financial problems.