Jessa and Ben navigate life as a family of three with their new baby; Jill and Derick settle into their home in Central America; Jessa enlists her sisters to help prepare a fall feast for the whole family.
Jana and Jessa embark on a lighting project while the rest of the family travels to Central America; Jessa and Ben go on their first date since Spurgeon was born.
Jessa goes out for coffee with Jana and Anna, leaving Ben in charge of Spurgeon; Jinger buys a car at auction; Jana starts a new project with her brothers; Jill and Derick introduce Israel to their love of pickles.
The siblings continue building the tree house, which gets bigger and bigger; Joy and Sierra secretly plan a surprise baby shower; Jill and Derick have surprise guests in Central America.
Work on the tree house continues, but cold weather hampers the family's efforts. Meanwhile, Ben and Jessa go to St. Louis to meet with Christian rapper Flame, and inspiration sends Ben into the recording booth.
The girls hit the road for a weekend getaway, but encounter an unexpected detour on the way to their destination. Meanwhile, the tree house is ready for a big unveiling after weeks of work.
Jessa, Ben and Spurgeon travel to Central America to visit Jill, Derick and Israel. As they prepare for the trip, they travel down memory lane, revisiting Jessa's milestone moments, from engagement to motherhood, that have led to this emotional reunion.
Jessa and Ben experience what life is like in a foreign country with a young son; Jill and Derick remember their beginnings together in Nepal and the adventures that have led them to Central America.