Joan (Helen Twelvetrees) is a Canadian, adopted by Ma Dawson (Nellie Ferguson), a struggling horse breeder and trainer. Joan thinks "legs don't make a race horse, it's blood", and so she buys an unwanted thoroughbred colt called Stormalong. Helped by Ma's son Tommy Dawson (Frank Leighton), Joan restores the horse to health and fitness, and soon enough the horse is winning race after race, becoming a favourite for the Melbourne Cup.

Daubeney Carshott, a concert pianist, leaves London to dive for pearls on Thursday Island in the South Seas at the whim of Stella Raff, his fiancée. Once there, he discovers that the life he leads as a pearl diver is better in every way than his former existence as a social-lion pianist. He meets and falls in love with Lorna Quidley, after learning this Stella had send other suitors off in quest of a giant pearl for her.