When Dr. Mike and Sully travel to Boston for Colleen's graduation from medical school, they find Dr. Mike's mother terminally ill. Sully finds himself a target for assassination by a corrupt politician.
| Actor | Role |
|---|---|
 Jane SeymourDr. Michaela 'Dr. Mike' Quinn | Dr. Michaela 'Dr. Mike' Quinn |
 Joe LandoByron Sully | Byron Sully |
 Shawn TooveyBrian Cooper | Brian Cooper |
 Jessica BowmanColleen Cooper Cook | Colleen Cooper Cook |
 Georgann JohnsonElizabeth Ann Weston Quinn | Elizabeth Ann Weston Quinn |
 Elinor DonahueRebecca Quinn Dickinson | Rebecca Quinn Dickinson |
 Jude BenyMartha | Martha |
| UUna KayMrs. Cook | Mrs. Cook |
| SSara McRaeKatie Sully | Katie Sully |