Betsy Jobs (Kirsten Dunst) and Arlene Lorenzo (Michelle Williams) are two lovable yet somewhat scatterbrained teenage girls navigating life in Washington D.C. during the early 1970s. Betsy hails from a privileged family in the upscale Georgetown neighborhood, while Arlene resides with her widowed mother in an apartment situated in the infamous Watergate building.
One fateful evening, seeking to mail a letter to enter a contest for a date with teen heartthrob Bobby Sherman, the girls sneak out of Arlene's home just as the Watergate break-in unfolds. They inadvertently manage to enter and exit through the parking garage after taping the latch of a door, leading to the discovery of the break-in. In their haste, they spot G. Gordon Liddy (played by Harry Shearer) and mistakenly believe he is engaged in a jewel heist, causing them to panic and flee. Their actions prompt a startled security guard to notify the police, leading to the swift arrest of the actual burglars.
The next day, during a school tour of the White House, the duo encounters Liddy once more. Though they remain unaware of who he is, he recognizes them and quickly grows suspicious. He points them out to H. R. Haldeman, who begins to interrogate them, uncovering their obliviousness to the President’s narratives. Their conversation is amusingly interrupted first by a call from Haldeman's wife, then by President Nixon himself, portrayed by Dan Hedaya, who sidles off with Haldeman to express his frustrations about the corrupt bugging operation.
Amazed to be in Nixon's presence, the girls are more enamored with his dog, which sparks an idea in the President’s mind. To ensure their silence regarding the events they've unwittingly witnessed, he appoints them as his official dog walkers, granting them access to the White House repeatedly. During their visits, Betsy and Arlene unknowingly influence significant political events—including the Vietnam peace negotiations and the Nixon-Brezhnev summit—by bringing along cookies that are infused with marijuana. Toward the film's end, Betsy’s brother, Larry (Devon Gummersall), discovers the cookies' "secret ingredient" and deduces that their consumption could explain Nixon's spiraling paranoia.
Meanwhile, Arlene, who initially idolized Bobby Sherman, finds herself smitten with Nixon. After recording an 18½-minute message of adoration into a tape recorder, she inadvertently plays back a clip revealing his grim and crude language, leading her to a harsh reality check about his character. Confronting Nixon directly—> "You kicked Checkers, you're prejudiced, and you have a potty mouth!"— they face his ire as he threatens and dismisses them: "You don't mess with the big boys!"
Reevaluating their position, the girls decide to spill all to the "radical muckraking bastards" at the Washington Post, namely Bob Woodward (Will Ferrell) and Carl Bernstein (Bruce McCulloch). They inadvertently become the identities behind the notorious Deep Throat (a humorous twist given that Betsy's brother had just been caught watching a film of the same name). However, Woodward and Bernstein are initially incredulous, portraying them as childish and incompetent. Matters are complicated when their sole piece of physical evidence, a list of names connected to the Committee to Re-Elect the President, gets eaten by Betsy's dog.
As Nixon's aides recognize the girls as a genuine threat, they resort to various tactics, including surveillance and infiltration, to glean what the girls know. The situation escalates to the point where they break into Betsy's home and pose as Arlene's mother's boyfriend. Pushed to their limits after being pursued by the Watergate “plumbers,” the girls take matters into their own hands. They sneak into Haldeman’s residence and manage to steal a crucial tape recording, providing a transcription to Woodward and Bernstein while keeping the tape as a "souvenir." This pivotal action ultimately leads to the downfall of Nixon's political career. Following his resignation, as his helicopter hovers over Betsy's house, the duo proudly displays a sign that reads, "You suck, Dick," further infuriating the now-former president.
