Mike receives an emergency telegram from her sister Rebecca -- her mother is gravely ill. Mike rushes to Boston to her mother's side, the Cooper kids in tow, where Dr. Mike and her ""roughhewn"" children are met with raised eyebrows by Dr. Quinn's own family. While consulting with Elizabeth Quinn's attending physician, Dr. Mike meets a handsome and progressive Doctor, Dr. William Burke. Dr. Mike's prognosis of her mother (hepatitis) differs with Mrs. Quinn's doctor, Dr. Hanson, who diagnoses cancer. Dr. Burke, however, believes Dr. Mike may be onto something. They have a lot in common and develop a strong mutual admiration for each other. They work together to cure Mrs. Quinn and some of Dr. Burke's other patients. Meanwhile, Matthew chafes at being stuck in Boston away from Ingrid, while Colleen appreciates the learned and cultured atmosphere and Brian adores the candy stores. Just when everyone has settled comfortably into the Boston routine, Sully shows up, unannounced and in buckskin

Sully arrives in Boston and discovers that he's facing worthy competition for Mike's affection in the form of Dr. William Burke. Sully at first settles uncomfortably into Mike's Boston surroundings, but later, with prodding from the kids, submits to a grand makeover. Later, Sully romances Mike with dining and dancing, even attending an opera together. At an all-male medical society, Dr. Burke steps aside so that Mike can present a paper on Indian medicine, while Sully looks on. Afterward, Sully overhears Dr. Burke proposing marriage to Mike and heads back to Colorado, but not before confessing his love to Mike. In the end, Mike declines Dr. Burke's marriage proposal and Mike and the kids return to Colorado, where Dr. Mike returns Sully's declaration of love with a vow in kind.

Mike and Sully go to the Reverend for a dose of preventative pre-marital counseling, and recall the path of their romance.

When Colleen, who is working on a college paper, asks Dr. Mike to recall her most memorable case, Dr. Mike looks back on the five turbulent years she's lived and loved in Colorado Springs. As they sit with Andrew, who is mysteriously ill at the clinic, Dr. Mike reminisces about her tumultuous career -- its successes and its failures -- and realizes how many divergent cases she has seen and treated.

When Andrew's condition takes a turn for the worse, Dr. Mike warns Colleen about the fine line between emotional involvement and professional detachment, an issue with which she has long struggled in the frontier town that's now her home.