Reboot. the first episode

part 2:

Part 3:

The first season of ReBoot was highly episodic, with each installment being a self-contained episode. Most of the episodes established characters, locations, and story elements, such as the gigantic “Game Cubes”. When “The User” loads a game, a Game Cube drops on a random location in Mainframe, sealing it off from the rest of the system and turning it into a “gamescape”. Bob frequently enters the games, “Reboots” to become a game character, and fights the User’s character to save the sector. If the User wins a game, the sector the Cube fell in is destroyed, and the Sprites and binomes who were caught within are turned into energy-draining, worm-like parasites called Nulls.