Doraemon is sent back in time by a young boy named Sewashi Nobi to improve the circumstances of his great grandfather, Nobita so that his descendants may enjoy a better future. In the original time-line, Nobita experienced nothing but misery and misfortune manifested in the form of poor marks and grades, physical disasters, and bullying throughout his life. This culminates in the burning down of a future business he set up which leaves his family line beset with financial problems. In order to alter history and better the Nobi family's fortunes, Sewashi sent him a robot called Doraemon.
Doraemon has a pocket from which he produces many gadgets, medicines, and tools from the future. The pocket is called yōjigen-pocket (lit. fourth-dimensional pocket). Some of the gadgets (dōgu) are based on real Japanese household devices with fanciful twists, but most are completely science fiction (although some may be based on folklore or religious stories). Thousands of dōgu have been featured in Doraemon. The number of dōgu has been approximated at 4,500. It is this constant variety which makes Doraemon popular even among adult readers/viewers. In the series, the availability of dōgu depends sometimes on the money Doraemon has available, and he often says some dōgu are expensive in the future. The more famous ones include the "bamboo-copter" (very similar to the ones that appears on the older series of Beany and Cecil), a small head accessory that allows flight; the "Anywhere Door", a door that opens up to any place the user wishes; and the "Time Machine". Some of the recurring dōgu appear also in Fujiko F. Fujiko's other works such as21-emon, Kaibutsu-kun, kiteretsu Daihyakka, Mikio to Mikio or Paman.
Although he can hear perfectly well, Doraemon has no ears: his robotic ears were eaten by some robotic mice, giving him a series-long phobia of the creatures.
The only main female characters is Shizuka Minamoto, who serves as a friendly interest for Nobita. Shizuka is intelligent and is Nobita's good friend. Nobita's main human friends and/or rivals include Takeshi (nicknamed 'Gian', from the English word giant), a consummate bully, and Suneo, a wealthy but cunning and arrogant brat. There are many recurring supporting characters, such as Dekisugi, Nobita's parents, Gian's mother, his school teacher, his descendants from the future, and Doraemon's little sister, Dorami.
The stories are formulaic, usually focused on the everyday struggles of fifth grader Nobita, the protagonist of the story. In a typical chapter, Nobita comes home crying about a problem he faces in school and/or the local neighborhood. After hearing him out, Doraemon often offers helpful advice to his problem(s), but that's never enough for Nobita, who is consistently looking for the "quick, easy" way out (which offers insight to the viewers as to why Nobita's life turned out the way it did). Finally, after Nobita's pleading and/or goading, Doraemon produces a futuristic gadget out of his aforementioned pouch to help Nobita fix his problem, enact revenge, or flaunt to his friends.
Unfortunately when in possession of the gadget, Nobita usually gets into deeper trouble than before, despite Doraemon's best intentions and warnings. Sometimes, Nobita's friends (usually Suneo or Gian) steal Doraemon's gadgets and end up misusing them. However, by the end of the story, there is usually retribution to the characters who end up misusing them, and a moral is taught.
With a lot of difficulties, Nobita becomes a grown up man and marries Shizuka. Doraemon falls in love with a white Persian cat, gets married to her and takes her to the 22nd century. They have a half-robot, half-cat daughter who they named Doraiko. There is another comic book called Doraiko. It is the story of Doraiko, who falls in love with a robotic dog named Shiro. They both lived in the 23rd century until Nobita's son and daughter-both are exactly like Nobita-need help. So Shiro and Doraiko go to the 21st century to help Nobiko and Norito.
History repeats with more gadgets...