Man's Best Friend

S3, E3: Jack and Lisa have their first big fight after Lisa tries to persuade Jack to get a new truck. Ty learns how to dance from Lou. Peter comes back to Heartland. After fights and misunderstandings, Ty and Amy get their act together, and Ty gives Amy a promise ring. That night, Ashley goes to a prom with a rich frat boy and tries to make Caleb jealous.