Season Four sees Amy Fleming continuing to work to heal and retrain neglected and abused horses. Special projects for Amy include training a racehorse to jump, saving abandoned horses, and keeping her relationship with Ty Borden, a once troubled teen, together. Lou, Amy’s sister, struggles to live two lives, one in Dubai, and one at Heartland, which takes a toll on her marriage. Jack and Tim, Amy’s grandfather and father, quarrel with their usual frequency, and the neighbour who never seems to leave, Mallory Wells, continues to get herself into sticky situations.