Following the Browns, a polygamist family comprising of a husband, three wives and 13 children that is on the verge of a change that could transform its dynamic.

Kody heads south to court his potential fourth wife, Robyn. Meanwhile back home, the wives express their true feelings about their new possible sister wife as they make preparations for Christine's new baby.

Kody and his teenage daughters throw a birthday party for his new fiancee Robyn, while first wife Meri struggles with feelings of jealousy

Robyn helps out with the children while Kody and pregnant third wife Christine go to the hospital

While the three wives buy a friendship ring for Kody's fiancée Robyn, Kody prepares to celebrate his 20th Anniversary with his first wife, Meri. But when nothing goes as planned, will Kody end up in the dog house?

As the wedding day nears, the three wives help fiancée Robyn pick a wedding dress, a cake, and a venue for their unique polygamist wedding reception. Meanwhile, it's Janelle's birthday and Kody has a special trip planned just for the two of them.

The big day is finally here! Follow Kody and his wives as they make Robyn officially wife number four. See this extraordinary family as they celebrate the newest additions to their family and prepare to embark on a new chapter in their lives.