On the eve of his departure for the New World, Allan MacDougall asks his beloved Harriet to wait for his return when he will be established and able to marry her. His parents discover his intent and find it dishonorable, so Allan is obliged to free Harriet from her promise, although he vows to remain faithful. On Prince Edward Island, Allan struggles against his father's tyranny to establish himself and to secure a home for Harriet. Meanwhile, back on the Isle of Mull, Harriet must face both danger and temptation as her own family's farm is threatened. It will be many years before Harriet and Allan meet again and their love will be put to the ultimate test.