The show stars three Earth children — Matt, Jackie and Inez — and Digit, a "cyboid" (a bird-like cyborg). The three kids and Digit use their math and problem solving skills to stop the evil deeds of the Hacker, a villain who breaks into Motherboard and MotherBoard's networks, and his two cyborg henchmen, Buzz and Delete.
The series takes place in Cyberspace, the electronic medium of computer networks, in which online communication takes place, with planet-like bodies called "Cybersites." Each cybersite is inhabited by "Cyborgs", the virtual inhabitants of Cyberspace. Some are based on real-world places, such as ancient Egypt and the American Old West, or fantasy worlds such as mythological Greece. The guardian of all Cyberspace is Motherboard; her repairman is Dr. Marbles.