Lisa meddles in Lou's business and personal life with disastrous results. Mackenzie comes back to Heartland to get married, but when a cursed horse also arrives, the wedding is almost called off.
Hollywood starlet Mindy Fanshaw arrives at Heartland under the pretext of honing her non-existent riding skills in anticipation of an upcoming role.
Jack's patience is tried as Tim recovers from his shooting injury at Heartland. Amy uncovers some surprises about an ex-owner of a horse she's hoping to re-home.
Much to her mother's dismay, Ashley is staying at Heartland and has promoted herself to VP of guest relations. Ty is still trying to make amends with Amy for his latest relationship snafu.
During a late summer heat wave, Ty's dad shows up with a truck full of sick, thirsty horses bound for the slaughterhouse. Amy recognizes one of the horses and the mystery deepens.
It's rodeo time. Amy decides to try team roping with Caleb until he has second thoughts. Meanwhile, Lou loses her Queen of the Rodeo contestant, Soroya.
With the Fall Finale only a few days away, Amy finds herself working with the enemy after Ben convinces Ashley that Heartland is the only place that can help her suddenly uncooperative horse.
Disaster strikes when the barn at Heartland erupts into flames and Jack is injured getting the horses to safety. Heartland may never be the same again after Lou discovers the barn isn't insured.
When Jack relents and allows Tim to visit Heartland, the simmering sibling rivalry between Amy and Lou heats to a boil.
Ty has a run-in with a cruel cowboy when the local ranchers round up some local mustangs for the veterinarian to test.
A girl from Ty's troubled past gets a job at Briar Ridge and comes to Heartland looking for him. When Mrs. Bell goes to the hospital after a heart attack, Lou becomes attached to her pony, Sugarfoot.
The pressure is on when a famous race horse, Gallant Prince, is sent to Heartland to see if it can be rehabilitated after being terribly burned and injured in a highly published stable fire.
Lou isn't pleased when a neighboring rancher brings a pregnant mare to stay at Heartland.
When Lou decides to make a promotional video to advertise Heartland, nobody is very supportive of the idea. But Lou is determined, perhaps even more than usual.
Amy debates what to do when she receives money from an unexpected source.
Amy enters Spartan into an endurance race after realizing he's not ready to retire.
Hudson hosts a lumberjack competition and Amy must retrain a Clydesdale to compete in the draft horse race.
The man who shot Ty returns to Hudson and Amy and the rest of the family grapple with how to react.
Tim and Jessica's small party snowballs, while Lou struggles to hide a past relationship from the family.
Amy and Shadow find themselves in jeopardy on a cattle drive. Parker and Katie are left to babysit Lyndy.