Horror mounts when a flu epidemic attacks Colorado Springs. Dr. Mike must attend the sick townspeople and protect others from getting the deadly disease. But being a lady doctor has people questioning whether she can handle the fatal epidemic.

A bitter Loren, who blames Sully for his daughter's death, tries to repossess Dr. Mike's cabin when he learns he still owns the deed.

When Mike and Sully stop to check on old Mrs. Johnson, they discover her dead and a young boy, Zack, hidden in the closet. Mike takes the child in and confronts the townsfolk, who reluctantly admit to knowing the boy's mother was one of Hank's whores. When she died they sent Zack to Mrs. Johnson because he was ""simple."" Mike is frustrated in her attempts to find a medical diagnosis and cure for Zack's condition. Mike's further detective work reveals that Hank is Zack's father, and she helps Hank own up to his responsibility.

Meanwhile, Brian seems to be the only one to get the boy to exhibit his artistic abilities, and he is mistakenly given credit for a drawing that Zack has done. Later, when Zack's artistic talent is discovered, Hank agrees to send him to an art school in Denver. The show has a cute opening scene of Mike and Sully with him criticizing her driving.

Halloween is trick-or-treat for the residents of Colorado Springs when Sully's dead wife, Abigail, haunts Dr. Mike, after Sully suggests fixing up the homestead for her. Eventually, Mike is able to lay Abigail's ghost to rest. Meanwhile, Brian becomes terrified after his investigations lead him to believe Dorothy is a witch. But, later she helps him deal with his sadness about the fading memory of his mother. Jake and Loren's prank on the town backfires when Jake pronounces a man dead and his ""corpse"" walks away -- Mike later diagnoses the man as a catalepsy sufferer.

Colleen and Becky become best friends when, at Bray's store, Alice, another friend, insists on taking Colleen's favorite fabric to make a dress for the Sweethearts' dance. Dorothy fears she may be pregnant when she faints in the general store. Mike assures her she is not, but she is beginning the ""change of life"". Later, Mike is frustrated when she tries to teach Sully to dance the Sweethearts' reel. Mike confides to Dorothy her fears about a physical relationship and Dorothy guesses Mike is a virgin. Meanwhile, Becky asks her new best friend, Colleen to ask Richard, a boy she likes, if he likes Becky. He asks Colleen if ""the girl,"" (he thinks it's Colleen) will meet him at the kissing tree. Colleen misunderstands, thinks he knows it's Becky. She tells Becky where to meet him, but Becky chickens out and Colleen goes in her place, to explain. Richard, assuming Colleen is there to meet him, kisses her. Becky finds out and is heartbroken. Becky and Alice team up against Colleen and spread

Tom Jennings, Dorothy's son, shows up in Loren's store one day when Mike and the kids are there shopping. He's a Civil War Veteran with an old war injury -- his leg was almost blown off. Dorothy asks Mike to treat him when he complains of pain in his seemingly healed leg. She gives him a syringe of morphine for the pain, not noticing his blissful expression. Mike invites he, Dorothy and Loren to dinner. During dinner, Colleen develops a crush on him. Sully's suspicion is piqued when Tom leaves and he forgets to use his cane.

The next day, Tom returns to Mike, telling her his leg hurts. She treats him, but denies him her last vial of morphine, which she's saving for an emergency. Later that day, Loren catches Tom slipping a vial of patent medicine from the store under his coat. When Dorothy confronts Tom, he replies that the pain just got to him, and complains that Mike won't give him any morphine. Later that night, he goes out and tries to mooch free drinks at the saloon. Later still,

Robert E buys a house in town. When the auctioneer, Jedediah Bancroft, sees that he's sold the house to a black man, he tries to renege, but Mike intercedes. Later, Mike is surprised to learn that Jake, Loren, Hank and Dorothy are displeased to have Robert E and Grace living in their midst.

That night, at the homestead, Matthew tells Mike he's been invited to join a new men's club -- the Ku Klux Klan, which he knows nothing about but is heading out the door to investigate. At the meeting, Jedediah, the leader of the group, promises only ""a big surprise"" for the following night, then adjourns the meeting. The next night, townsfolk don white gowns, recite the KKK oath, and ride out to harass and beat Robert E. After treating Robert E, Mike storms into the barbershop, where she confronts Jedediah, Jake, Loren and Hank about the events of the night before. Jedediah tries to make offers to get Robert E and Grace out of town, even threatening Mike with the mortgage on her clinic if Robert E

Rev. Johnson's in love with the town's new schoolteacher (Sherry Hursey), while Mike's concerned about the woman's wanton use of corporal punishment in the classroom.

Mike remains the sole voice of reason when townsfolk read a newspaper article predicting that a comet will end the world. Also, Mike addresses the Cooper kids' fears about ""the end."" Hank and Loren cash in on hysteria.

When teen-outlaw Belle Starr robs the saloon, Mike takes her in, intending to reform her; Colleen overcomes her fear of riding. Belle Starr: Melissa Clayton.

With no child-protection laws, and influenced by Charles Darwin's theory of evolution, Mike has a girl removed from her ""guardian"" by taking the man to court and trying him for animal abuse. Mary Ann: Doren Fein.

Mike is overwhelmed with her new found passion for Sully, and feeling slighted, Colleen joins her schoolmates for dangerous and questionable escapades.

Michaela has returned to work after being home with Katie. Between work, the baby and being so tired,Michaela is spread thin. Sully feels neglected. Sully helps Michaela through this difficult time. Colleen is accepted to college in Denver.