Travis teams up with a religious and fanatic couple, named Adam and Beth Dorsey, whom he met via Gellar's blog, to kill Holly Benson (the former Whore of Babylon whom he let go) and to unleash the next tableau, Wormwood, a poison which Travis re-imagines as poison gas. Dexter tries to get one step ahead of the Doomsday Killers and figure out where their next victim could possibly be before they attack again. Meanwhile, Debra begins to realize she relies too much on her brother after reacting to a crime scene.
The Miami Metro Police Department, led by FBI Special Agent Frank Lundy, begins the hunt for the "Bay Harbor Butcher". Both Dexter and the police are hunting for Little Chino, and Dexter is determined to kill him properly given a second chance. Debra and Dexter struggle to overcome memories of the encounter with Brian that led to his death. After Paul's funeral, Rita confronts Dexter about his involvement in Paul's death, and he admits to having an addiction, which Rita infers to be to drugs. LaGuerta shows surprising support for new boss, Lieutenant Esmee Pascal (Judith Scott).
The episode opens late at night on the day before election day. Josh finally relaxes long enough to see various campaign staff hooking up, and he and Donna sleep together – twice. Election day brings stress in both campaigns: Josh is convinced he is finding problems in exit poll data, while the Vinick campaign worries the data shows them losing in key places. West Virginia is unexpectedly called for Vinick and the traditionally Republican South Carolina is called for Santos. The episode closes with Annabeth finding Leo in his room, her screaming for help, and Secret Service agents closing in calling over their radio, "He's down, he's down!"
Bartlet makes a life-or-death decision regarding the defense minister of Qumar who is a known terrorist. The flirtation between C.J. and her Secret Service bodyguard, Simon Donovan, is limited by their professional relationship and then cut short by tragedy. Josh defeats Amy in the welfare bill battle and their relationship is left with an uncertain future. Bartlet encounters his opponent, Governor Ritchie, at a performance of War of the Roses.
A student (Vicellous Reon Shannon) who just graduated from Princeton experiences severe spasms at a graduation party. Meanwhile, House's parents drop by but he is reluctant to see them, igniting curiosity among the hospital staff.
When the flash of a secret nuclear detonation is detected over the Indian Ocean, President Bartlet calls upon his people to investigate which nation now has the atomic bomb. As conventional thinking favors Iran, the President orders bombers into the air to destroy that nation's most likely uranium-enriched targets. Meanwhile, Josh chides NASA personnel on the future of space exploration — until he is introduced to an attractive female administrator. C.J. fumes when a combative television talk-show host, Taylor Reid, denigrates her on the air, and Will discloses to Vice President Russell that Russell is considered a buffoon by the White House staff. However, it is Russell who manages to dissuade the President from bombing Iran.
The staff debates whether to counter a fast-rising Republican presidential candidate's verbal assault on affirmative action at the Iowa caucuses and Josh postpones his tropical vacation with women's rights advocate Amy Gardner to defuse a risky situation in Vieques, Puerto Rico. C.J. surprises Toby with her lack of enthusiasm for affirmative action, while Sam has to meet with a UFO crackpot per Leo's orders. Toby and President Bartlet clash over the President's mental state and relationship with his father.
During a speech at an awards dinner, President Bartlet announces his nomination of one Democrat and one Republican, each known to favor reforms, to fill two vacant seats on the Federal Election Commission. A powerful Republican senator wages battle with the West Wing staff. Leo cautions the senior staffers not to make mistakes this week, and C.J. tells Mandy that Leo prefers that Mandy stay out of his way due to her involvement in the leaked memo. Leo arranges for Toby and his ex-wife, Andrea "Andy" Wyatt, a member of the House of Representatives, to meet and discuss legislative matters, and the two eventually reach an agreement against minimum sentencing for drug users. Al Kiefer, Joey Lucas, and Kenny arrive from California to help with the confirmation of the nominees. Josh and Toby tell Sam that his relationship with Laurie has become known to one of his political enemies. The senior staff confer with the President in his bedroom at midnight with positive and constructive results.
The Senate confirms President Bartlet's nomination of Judge Mendoza to the Supreme Court, prompting the West Wing staff to celebrate and C.J. to lip-sync to "The Jackal". The next day, however, ushers in a myriad of problems that bring the senior staff quickly back to Earth. Zoey attends a frat party which was the location of a Metro Police drug bust and subsequent arrest of the son of a major fundraiser for the Democrats after her departure. A reporter for a conservative newspaper tries to cause problems while C.J. and others try to minimize it as a non-story, which becomes more of a struggle when C.J. discovers that Zoey did not tell her the whole truth. Mallory, Leo's daughter, quarrels with Sam about school vouchers. Mandy asks Toby for help in getting a replacement panda from the Chinese government and gets him to help her to cause pain for Josh. Meanwhile, due to an objection by a member of the Senate Judiciary Committee, Josh has a long and vigorous discussion about reparations (of $1.7 trillion) for slavery with a candidate for an appointment to the post of the Assistant Attorney General for Civil Rights.
Elections are underway in Kazakhstan, but Russia and China teetering on the brink of an oil war in Central Asia is the least of Bartlet and C.J.'s concerns as they face a nuclear reactor in California on the verge of a meltdown. While agonizing over whether to evacuate nearby citizens and release radioactive steam into the atmosphere, the Santos and Vinick campaigns stare each other down, trying to avoid being the first to turn the crisis into a political issue – all the more complex as, decades ago, Vinick lobbied for the plant's construction, while Santos has spoken about the dangers of nuclear power. When the news comes out, the election becomes, in Josh's words, "too close to call."