It's late afternoon in Coal Valley and Elizabeth has just dismissed her class for the day. As the students filter out of their classroom, Jack Thornton wanders in to speak with Elizabeth. Having finally come to grips with his feelings towards her, Jack makes his first true romantic gesture towards Elizabeth. Hoping to make up for his last attempt at a date, Jack invites Elizabeth to dinner. With some help, Jack plans a romantic candlelit meal for two in Abigail's cafe. Little do Jack or Elizabeth realize that the arrival of a stagecoach will usher in surprises that could upend the lives of everyone in Coal Valley.
The first surprise to exit the stagecoach is another Mountie, Constable Patrick O'Reilly. Jack immediately greets the constable and puzzled, asks him, "Where's your horse?" As Constable O'Reilly replies, "She wanted to make a grand entrance," a young aristocratic woman comes galloping along. Elizabeth screams out load as she suddenly recognizes her sister Julie. The two women embrace, but from the moment she dismounts her horse, it's clear that Julie is completely consumed with the fairytale romance between her sister and Jack.
In the meantime, Jack helps Julie's personal escort, Constable O'Reilly, get settled into his quarters. Constable O'Reilly, a man of high rank and experience, has spent the last 15 years chasing outlaws on the frontier. Curiosity piqued, Jack asks O'Reilly why a man of such stature would bother with a simple escort assignment. O'Reilly explains that having recently gotten married and now expecting his first child, his priorities have changed and he's decided to settle down. What Jack hadn't expected is that his months old request for a transfer has been accepted and O'Reilly is in Coal Valley to replace him. Jack is now confronted with the difficult decision of following his dreams or following his heart. And while a future with Elizabeth seems within his grasp, a refusal of his transfer could mean the end of his career as a Mountie.
At the same time, Abigail’s new career venture appears to be taking off. While business is going well, she does have one persistent problem, the regular appearance of Mr. Henry Gowen. While Mr. Gowen is becoming more and more infatuated with his new business partner, Abigail struggles to hide her disdain for the man. What's more, Jack confides in Abigail that he may have evidence that the company cut corners to save money which may have led to the tragic mine explosion. Abigail tells Jack that leading up to the accident, her husband had been "locking horns" with Mr. Gowen and that his safety concerns may have been the reason why. Jack asks for Abigail's help in conducting the investigation, to, which she agrees. The opportunity to further investigate their suspicions comes when Mr. Gowen attempts to ask Abigail for a date. While she flat out rejects his advances, she does concede that as business partners they could meet for a strictly professional lunch in his office. With he opportunity now available, Abigail sets out to get more information on what caused the tragic mine explosion.
Meanwhile Julie has found a way to stumble into her own risky situation. While accompanying Elizabeth and her students on an outdoor entomology excursion, Julie takes a moment to explore the wilderness. While in the forest, Julie comes across Mr. Spurlock's old shack. Curiosity leads her inside where she encounters a young man, brandishing a gun. The man is clearly injured, bleeding profusely from a gunshot wound in his back. Claiming his injuries were a result of his chasing outlaws, Julie offers to get him some bandages, alcohol, and food. He reluctantly accepts and introduces himself as Nathaniel. What Julie doesn't know is that Nathaniel is the accused leader of the infamous and elusive Tolliver gang. Responsible for numerous train and back robberies in the region, The Tolliver gang is among the most wanted criminals on the frontier. Later, when Julie returns with the supplies, Nathaniel reveals his felonious past, but says that his older brother is the mastermind of the gang and that he, Nathaniel, was never given a choice but to live a life of crime.
Revelations continue to come forward when Jack finally tells Elizabeth about his transfer orders. A heartbroken Elizabeth confides in Abigail, who in turn reminds Elizabeth that nothing will stand in the way of true love. Jack too gets advice from Gabe, one of Elizabeth's young students. Gabe tells Jack that even at his young age he is certain of the girl he will marry. Gabe tells Jack that "sometimes you see a girl and your whole future is clear as a bell." The sentiment hits Jack so hard that he decides to reject his transfer orders. But when Jack tells Elizabeth of his decision she emotionally refuses to let Jack abandon his career for her. Certain that it will lead him to resent her, Elizabeth tells Jack that he must leave Coal Valley. As difficult as the decision is, Jack concedes and prepares to head out of town. Before riding off Jack tells Constable O'Reilly that he has left files on the mining accident for him and that Abigail can be a useful ally in the investigation. Constable O'Reilly thanks Jack and promises to keep Elizabeth safe.
Meanwhile, Julie's new friend Nathaniel has developed sepsis as result from his wounds. Burning up with fever, Julie has no choice but to bring him into Coal Valley for immediate medical attention. As the rain comes down Julie and Nathaniel arrive at Abigail’s door. Julie yells for help and the women rush to get Nathaniel inside. Later, the town doctor arrives to dress Nathaniel’s wounds and sedate him. He tells the women that Nathaniel's condition is precarious at best. His critical injuries and lackluster story leave Elizabeth on edge. Julie assures Elizabeth that Nathaniel will be no trouble and that if anything should happen Jack will certainly come to their rescue. Her flippant attitude sends Elizabeth over the edge, and a flood of emotions runs over her. She weeps for Jack and lambasts her sister for living in a fairytale world. But broken hearts are not the only concern running through Coal Valley. As the rain clears the next day, a wanted poster with Nathaniel "Nate" Tolliver's picture arrives at the General Store. With a notorious outlaw in their midst, it seems that Jack's leaving could not come at any worse of time for everyone in Coal Valley.