Natalie is running for the school board in an effort to keep Julie's school from being closed. She's set up her office in an abandoned storefront, and she has a crew of supporters helping her with signs, mailings, and phone calls. Suddenly, shots ring out, and the office is riddled with bullets. Monk, Stottlemeyer, and Disher go to a nearby rooftop, where they find a dead security guard and a note from the sniper that demands that Natalie withdraw from the race. Interestingly, Natalie's last name is misspelled on the note. Monk also finds a spent shell casing with Russian markings.
Their first suspect is Natalie's opponent in the election, Harold Krenshaw. Krenshaw is a fellow patient of Dr. Kroger's who drives Monk crazy, but he quickly proves to be innocent. Despite the continued threat, Natalie refuses to quit the race. Stottlemeyer assigns Disher to be her bodyguard, and Monk steps up the investigation. He keys in on the misspelled sniper's note and makes a realization: the misspelling on the note was the same as the misspelling on a campaign poster outside Natalie's headquarters. The sniper didn't really know Natalie's name - all he knew was what he read on the poster. The shooting wasn't really about the election! It was about something else!
Later, Natalie, Monk, and Disher are in Natalie's house rehearsing for a big debate with Krenshaw when someone throws a grenade through the window. The grenade explodes and they narrowly escape death. But they get another clue: the grenade was made in Chechnya. The same person who shot up Natalie's campaign office is still hard at work...
Then, it's time for Natalie's big debate with Harold Krenshaw. At the debate, one of Natalie's campaign volunteers, Jack Whitman, hands Monk a flyer, and eureka! The flyer is folded in a distinctive way that matches the sniper's note. Jack Whitman must be the killer! Monk doesn't yet know why, but he'll soon find out: Monk spots an empty carton of copier ink cartridges that Whitman left in Natalie's office. The carton is from a copy company that went out of business, but it matches the brand of copier Natalie has in her office.
Monk puts it all together: six months ago, Whitman was trafficking illegal weapons out of his office. An important document got jammed in his copy machine just as he was arrested by the ATF. Whitman went to jail, and the copy machine got sold to Natalie during a police auction. Whitman had to get to that copier, but before he could, he saw that a repairman was about to open up the copier. Acting fast, Whitman grabbed a gun and shot up the office, making it look like he was trying to kill Natalie when he was actually trying to shoot up the copy machine so nobody would open it up. Then he volunteered for Natalie's campaign and waited for an opportunity to get at the copy machine - but it never came. Unfortunately for Whitman, Monk figured out his plan before he could carry it out.
While Natalie eventually loses the election, Monk comes out a winner - by putting Jack Whitman behind bars.