Adrian Monk is horrified when he learns there is going to be a blue flu in San Francisco. He doesn't understand what the blue flu is—but it sounds terrible. Captain Stottlemeyer explains that it's not really a virus: the police force plan to call in 'sick' until they get a better contract. The good news is that the labor dispute will give Monk a chance to get back on the force. The bad news is that it means he'll be a 'scab'—and he doesn't like the sound of that either.

Before he knows it, Monk has his badge back and his own squad to command. Unfortunately, some of the squad members make Monk look like a paragon of mental health. But despite the challenges, they will have to pull together to catch an astrologer's killer, solve a series of mysterious fatal assaults, and, most importantly, clean up their desks.