Three-year-old Luke is starting to recover from his cardiac operation to the relief of his mother. For five-year-old Chantelle, however, her chest pain may mean a return of her heart problem. Cardiac specialist Joe Giovanni, who has looked after her since she was born, must use a rare and risky technique to assess the problem. And 15-year-old Arslan arrives on a stretcher with a broken leg after a rugby accident.