A robotic cat named Doraemon arrives from the 22nd century, sent by Nobita Nobi's great-great-grandson, Sewashi, to change the boy's miserable future. In the original timeline, Nobita’s laziness, poor grades, and bad luck lead to financial ruin for his descendants, prompting Sewashi to intervene by leaving Doraemon with his ancestor.

The series is set in a quiet, fictional suburb of modern Tokyo, where Nobita is a fourth-grade student who struggles with almost everything. He frequently arrives late to school, scores zero on tests, and is the main target of the local bully, Takeshi "Gian" Gouda, and the sneaky, rich kid Suneo Honekawa. Despite these hardships, Nobita is kind-hearted and imaginative, often dreaming of a better life. His best friend is Shizuka Minamoto, a smart and gentle girl who serves as his primary love interest.

Doraemon is a cat-shaped robot who lacks ears—having been bitten off by a robotic mouse, which gave him a lifelong phobia of the creatures. From his four-dimensional pocket, he produces futuristic gadgets known as "secret tools" to help Nobita. Iconic devices include the Anywhere Door, which opens to any location; the Bamboo-Copter, a small headpiece allowing flight; and the Memory Bread, which imprints information onto a slice of bread for eating and studying.

Episodes generally follow a recurring pattern. Nobita returns home crying about a problem caused by Gian, Suneo, or his own failures. Doraemon reluctantly offers a gadget to solve the issue, but Nobita often misuses it out of greed or revenge, leading to even greater chaos. The story typically concludes with a moral about responsibility and the limits of relying on technology. This formula is occasionally expanded into longer, more serious narrative arcs, particularly in the annual film adaptations. In these movies, the group of five travels to prehistoric times, parallel worlds, alien planets, or fantastical realms, transforming from everyday children into true heroes who rely on courage and friendship rather than just gadgets. The core cast is rounded out by Hidetoshi Dekisugi, Nobita’s talented and handsome classmate who is a rival for Shizuka’s attention. Through his adventures with Doraemon, Nobita slowly learns to overcome his weaknesses, demonstrating the show’s emphasis on perseverance, empathy, and the importance of self-reliance.