Sully is appointed Indian agent to the Cheyenne and approaches it in an idealistic fashion. When the food intended for the tribe is diverted and illegal alcohol is plentiful, Sully becomes angry. He vows to discover the truth with the help of Dr. Quinn and her family.

Dr. Mike convinces Robert E to take a job fixing a train boiler, then finds out it is a dangerous job.

When Dr. Mike becomes the substitute school teacher, the town gets upset when she teaches the children about evolution.

Dr. Mike and Sully convince Chief Black Kettle that he should move his starving people to a new reservation. Dr. Mike and Sully are both working on wedding presents for each other.

When Dr. Mike and Sully hear there is trouble for the Cheyenne at their new home, they travel there with Cloud Dancing only to find the whole tribe was massacred. Dr. Mike is devastated after the massacre because she felt she should have stopped it.

While on his way to resign as Indian Agent, Sully discovers Loren badly injured in the wilderness and must battle his own despair in order to save him. Meanwhile, Dr. Mike is worried about Brian who is consumed with his efforts to build a flying machine.

Dr. Mike and Sully go to Rev Johnson for a honest discussion regarding their upcoming marriage.After originally agreeing they have no conflicts, the couple begin reliving their past difficulties via prior show clips since they first met.

The town of Colorado Springs is preparing for an event of a lifetime, the marriage of Sully and Dr. Mike. Unexpected guests include Dr. Mike's mother Elizabeth Quinn and two of her sisters Rebecca and Marjorie. They have brought with them enough Boston finery to pull off a splendid society wedding. Meanwhile General Custer has put out a bounty on Cloud Dancing which could interfere with the wedding.

Bolstered by the long-awaited arrival of the railroad, the citizens of Colorado Springs busily prepare for the biggest social event in the town's history, the wedding of Dr. Mike and Sully. The first train carries some surprise visitors, Dr. Mike's mother, Elizabeth, and sisters Marjorie and Rebecca, who have unexpectedly traveled all the way from Boston for the occasion. However, their elaborate wedding plans threaten to ride roughshod over the townsfolk's more homespun arrangements. Sully, meanwhile, is crestfallen to learn that Gen. Custer has placed a bounty on the head of his close friend Cloud Dancing, who he had planned to have as his Best Man.