Dilbert discovers that the office is inhabited by a race of former employees who have been "downsized" (literally shrunken down to size after they've been laid off) after finding all of his belongings used, the dry-erase markers disappearing, and X-rated websites on his computer.

On the eve of the new millennium, everyone — except Dilbert — is making New Year's plans. While assuring everyone that the company is prepared for Y2K, Dilbert discovers that the computer mainframe's main processor isn't Y2K-compatible and all the company's systems will crash if it isn't fixed. Dilbert is rewarded for discovering this by being assigned to fix it, and he discovers that the system's original programmer was Wally. But have years of drudgework dulled his brain too much to be able to tackle this crucial task?

Dogbert becomes rich and famous by writing a best-selling book about an imaginary disease, 'Chronic Cubicle Syndrome', and Dilbert finds himself saddled with the job of devising a cure.

The Boss decides that the company needs to merge with another, and chooses a company of brain-sucking extraterrestrials.

Dilbert is unwillingly promoted to management and given an assistant, sparking a showdown with the other engineers.

Dilbert and his co-workers find an empty cubicle and start dumping their obsolete computer equipment into it. To keep the marketing department from claiming the cubicle, they hack into the human resources database and create a profile for a fake engineer named Todd. The plan backfires when Todd is named project leader and develops a messianic reputation.

Dilbert tries to buy a computer online but gets the wrong model, leading to an unpleasant surprise when he tries to return it to the company warehouse.

After the company employees are forced to take ethical-training classes, Dilbert is put in charge of designing a nationwide Internet voting network. His scruples are put to the test when an attractive female representative of a tobacco special-interest group tries to seduce him.

Ratbert accidentally sends Dilbert's model rocket into space. When it returns with samples of DNA from aliens, cows, hillbillies, engineers, and robots, it rectally impales Dilbert, impregnating him.