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

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.

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.

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

The Henricksons embark on a 2,500-mile road-trip pilgrimage to a Joseph Smith shrine in Cumorah, NY, where Bill intends to bury a family time capsule in the sacred earth. Along the way, a series of jarring revelations test the limits of their family bonds--and Bill's faith.

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.

Bill convinces Ray Henry to go along with his idea to rescue a kidnapping victim; Nicki has a surprise visitor; Alby hatches a deadly plot to consolidate his power; Sarah makes a surprise announcement that shocks the family.

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.

To Roman's surprise, Bill and Joey attend the UEB priesthood council meeting. Alby's visit to Wanda brings out her old habits, which could potentially land Bill in a big trouble. Rhonda uses the acting competition as an excuse to leave the compound but she discovers that her family isn't willing to let her go. Finally, Barb attends the Mother of the Year awards ceremony but not all goes as expected.

Nicki goes back to the compound for a family reunion, bringing Bill with her, where they find out the extent of Roman's betrayal of their family. Barb is annoyed by Margene and Ben's behavior. Meanwhile, Alby disobeys his father.

Bill and Roman butt heads when Rhonda disappears from the compound. The prosecutor offers Joey a plea bargain in exchange for a confession. Meanwhile, Sarah takes an interest in a boy from her support group.

Bill is stressed out by work, and Frank tries to get a hold of Lois' money. Meanwhile, the family discovers Ben and Brynn's secret.

In the season finale, the family prepares for the annual Pioneer Week. Bill and Alby butt heads over the control of UEB. Meanwhile, Margene reveals the truth to Ana.

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.

Bill attempts to drive a wedge between Alby and Roman, whose case finally goes to trial. Struggling with the decision of what to do regarding her pregnancy, Sarah recruits Heather and Ben for moral support.

Bill petitions the DA's office to charge Roman with murder; Margene starts a jewelry business; Don's fact-finding mission about the casino license reveals the possible involvement of Bill's brother-in-law; Sarah considers her options for the future.

Barb finds out that her mother is about to re-marry. Bill hears disturbing news about Weber Gaming. Meanwhile, Nicki is upset by outside influences on her children.

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.

Nicki suspects that Bill is having an affair and is considering bringing a fourth wife to the family. Margene, feeling alone in the big house, befriends the new neighbor, Pam Martin. Bill goes after Roman and tries to expose him, but polygamy accusations also fly in the Home Plus. Meanwhile, Ben is trying to cope with his arousing sexuality and being a teenager.

The Henrickson's prepare Teenie's baptism with friction and surprises from Barb's judgmental sister. Bill decides to take preemptive action against Roman with his brother. Margene continues to butt heads with Nicki, and her misfortunes pile up. Ben wants to show his affection to Brynn but is surprised when she demands something more.

Nicki's problems escalate at home and on the job; Alby's wife Glory reacts to her reduced stature at Juniper Creek by showing a secret document to Bill; Joey's plans to make Kathy his second wife could be derailed by Roman and Hollis Greene.

Nicki's homecoming, after a visit from her sister wives, isn't what she imagined; Barb endures a trying experience at her old church; Ted does an about-face on the casino project; Scott's reunion with Sarah doesn't go over well with her father or brother; Joey is upset by Bill's change of heart about Roman after the Greenes' latest move.

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.

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