It's been four months since Ty's sudden and unexplained departure, and Amy has moved on and become used to working with Caleb Odell, Heartland's new stable hand. With Amy's 16th birthday just days away, Lou is busy planning a surprise birthday party for her sister.

Ty asks Amy to give their relationship another chance. Ashley makes a decision that surprises her mother and Lou. Cattle rustlers hit Big River Ranch, and the situation gets out of hand.

It’s a week before Christmas and holiday preparations are moving into high gear at Heartland. Lou’s new husband Peter may not be able to spend Christmas with her due to his father’s illness. Amy, Ty, Jack and Tim head out on a rescue mission when an anonymous call is received about starving, abandoned horses trapped in an avalanche. And Caleb and Ashley discover you don’t need expensive gifts to have the perfect Christmas.