With the grand opening of the Blackfoot Magic Casino only days away, the Henricksons make last-minute preparations. Meanwhile, the feds probe the whereabouts of Roman Grant; Adaleen shares a shocking secret with Nicki; Margie makes an on-air slip-up; Bill and Nicki's smarmy ex, J.J. Walker, work out an arrangement allowing Cara Lynn to stay at the Henrickson's.

Ignoring pleas from Nicki to become Juniper Creek's next prophet, Bill contemplates running for the vacant Utah State Senate seat. Joey and Wanda return to Juniper Creek, but a suspicious J.J. is lurking. Sarah and Scott forgo a wedding in Bill's church in favor of a civil ceremony, shocking Barb. Margene confronts Nicki about her feelings for Ray Henry.

Bill, Nicki and Cara Lynn travel to Washington, D.C., where Bill tries to land an endorsement from Congressman Clark Paley while mending things with Nicki. Meanwhile, Margene's on-air triumph is tempered by a case of mistaken identity; Joey goes to extremes to safeguard a secret; and Barb and Sarah hit a young Native American woman with their car.

Pressed by Coburn to state his intentions, Bill gets his family to stage an elaborate rally announcing his candidacy. He isn't so lucky when an audit uncovers insurance discrepancies caused by his multiple wives. To protect his secret and save his candidacy, he ends up asking Don to take the fall, and moves up his announcement by three days.

Bill pulls out all the stops to win Paley's support for the State Senate nomination, while Nicki continues as his campaign's 'secret weapon.' Meanwhile, Margene gets the cold shoulder; Marilyn pitches to represent the casino's interests in Washington; Frank picks a bad time to drop by the casino; and Bill absorbs a last-minute sucker punch from Coburn.

Ana resurfaces with a surprise revelation. Meanwhile, Bill tries to get Tommy and Jerry to rebrand the casino; Marilyn makes yet another impressive pitch; Lois and Frank take Ben and Jodean south of the border; Nicki is infuriated by Alby; Margene worries about her booming business; and, with a flourish, Bill shows his wives the family's collective future.

With a revenge-minded Joey in tow, Bill makes an emergency trip to Mexico after Lois and Frank's latest smuggling escapade backfires. Nicki is jolted by a doctor's news, but even more flummoxed by Adaleen's shocking revelation. Margene offers up a novel remedy to keep Ana from leaving the country with her fiance, Goran. A bomb scare rocks the casino.

Sarah makes an announcement that shakes up the family; Nicki tries a new look; Margene is put on the defensive when Bill questions her real reasons for getting married. An ill-timed remark puts Barb in an unwanted spotlight; an exposed Marilyn looks to bring down Bill; Bill looks for clues about J.J. in Kansas, while Adaleen finds them closer to home.

With the election only days away, Bill puts the squeeze on Paley to protect his candidacy. But Marilyn has an ace up her sleeve that threatens to wreck Bill's chances. Meanwhile, Nicki gets news that seems too good to be true; and a late-breaking polygamist scandal forces Bill and his three wives to rethink their bold post-election plans.

After being elected state senator, Bill Henrikson announces that he is a polygamist, and he and his families are attacked from every side; Alby Grant returns from living in the desert with the idea of purifying the compound and getting revenge.

After revealing his polygamy to the world the newly elected Bill goes even further out on a limb by calling publicly for more polygamists to come into the open while Barb talks Nancy, her mother, into attending a mother-daughter symposium.

The Henricksons' holiday cheer is tested by family revelations. Alby's purification of Juniper Creek leads to a defection.

Bill fights for his right to be sworn in as senator; Barb, Nicki, and Margene struggle with personal revelations and changed public profiles.

Bill finds success in the Senate but finds new roadblocks set up by the Mormon church. Barb comes to a new conclusion about her life. Cara Lynn's adoption faces a new obstacle. Lois recalls her past with Frank.

Bill refuses to give in to Barb's vision of the church; Nicki chafes at the status quo; Margene looks to rally the children of polygamy.

Bill eyes a wedding as a chance to reseal his commitment to his wives; Alby makes a game-changing power play.

Bill fights for his family and his freedom; Alby looks to settle unfinished business; Nicki plans a new future for Cara Lynn.

Alby gets Adaleen on his side against Bill and his family. Rhonda asks Ben to marry her which results in Ben & Heather breaking up. Bill faces the possibility of a 20 year sentence, as his family tries to cope. Cara Lynn breaks down after Nikki tells her that Mr. Ivy never loved her.

In the series finale of Big Love, Margene plans on going on a cruise by herself to help people, Barb prepares to get baptized in the new church, and Nikki fears that she will be left alone if Bill goes to prison.