New South Wales, 1856: Miles McGinty and Isabel Dowling are born on the same night into different worlds. Miles is the illegitimate son of an actress in a troupe of travelling players, Isabel the rebellious daughter of a merchant banker, her home a red-brick mansion in one of Sydney's better suburbs. Both are destined to defy convention - and gravity. She rides in a balloon at the age of seven, defying the tweed-coated official who'd asked for a boy. He learns to float in mid-air with the aid of a mysterious showman and storyteller. But Miles becomes possessed by a secret ambition, the desire to build and ride in a flying machine. When his path finally crosses Isabel's, he knows he's met the only person who can share his adventurous vision.