Speaking of tennis, Polly Fitzpatrick will never know that if she hadn’t ridden her bike in front of Rachel Crowley’s car that day, she would have received a tennis racquet for her seventh birthday from her Auntie Bridget. Two weeks later she would have turned up for her first tennis lesson, where after twenty minutes her coach would have gone over to his boss on the next court and said quietly, ‘Come and see this kid’s forehand,’ and the swing of her racquet would have changed her future as swiftly as it changed when she swung the handlebars of her bike to follow Mr Whitby.

Polly will also never know that Mr Whitby did hear her call out to him that terrible Good Friday, but pretended not to, because he was desperate to get home and put his ludicrous fish kite back in the cupboard, along with his equally ludicrous hopes about another chance at a relationship with his goddamned ex-girlfriend, Tess O’Leary. Connor’s crippling guilt over Polly’s accident will help put his therapist’s daughter through Year 9 of private school and will only begin to ease the day he finally raises his eyes to meet those of the beautiful woman who owns the Indian restaurant where he has his post-therapy curry.

Tess O’Leary will never know for sure whether her husband Will is the biological father of their second child, the result of an accidental pregnancy conceived one strange April week in Sydney. The pill only works when you take it, and she’d left the packet behind in Melbourne when she flew to Sydney. Not a word will ever be spoken of the possibility, although when Tess’s adored teenage daughter mentions one year at Christmas lunch that she’s decided to be a PE teacher, her grandmother will choke on a mouthful of turkey, and her mother’s cousin will spill champagne all over her handsome French husband’s lap.

John-Paul Fitzpatrick will never know that if Janie had remembered the doctor’s appointment that day in 1984, her doctor would have listened to her describe her symptoms and, after observing her unusually tall, long skinny body, would have tentatively diagnosed her with a condition called Marfan Syndrome; a incurable, genetic disorder of the connective tissues, thought to have been suffered by Abraham Lincoln, involving elongated limbs, long thin fingers and cardiovascular complications. Symptoms include fatigue, shortness of breath, a racing heartbeat and cold hands and feet due to poor circulation, all of which Janie experienced on the day she died. It’s a hereditary condition, probably also suffered by Rachel’s aunt Petra who dropped dead when she was twenty. The GP, who thanks to an overbearing mother, was a high achiever and an excellent doctor, would have got on the phone and arranged an urgent appointment at the hospital for Janie, where an ultrasound would have confirmed her concerns and saved Janie’s life.

John-Paul will never know that it was an aortic aneurysm that killed Janie, not traumatic asphyxiation, and that if the forensic pathologist who’d done Janie’s autopsy hadn’t been suffering from a debilitating flu that day, he would not have been so willing to acquiesce to the Crowley family’s request for a limited autopsy if possible. Another pathologist would have done the full autopsy and seen the evidence, clear as day, of an aortic dissection, the indisputable cause of Janie’s death.

If it had been any other girl but Janie Crowley in the park that day, she would have staggered, gasping for air, when John-Paul realised what he was doing before the seven to fourteen seconds it takes for the average man to strangle the average woman and dropped his hands, and she would have run, tears streaming, ignoring his shouted apologies. Another girl would have reported John-Paul to the police, who would have charged him with assault, sending his life ricocheting in an entirely different direction.

John-Paul will never know that if Janie had gone to her doctor’s appointment that afternoon, she would have had urgent lifesaving surgery that very night, and while her heart was recovering she would have phoned John-Paul and broken his heart over the phone. She would have married Connor Whitby far too young and divorced him ten days after their second wedding anniversary.

Less than six months later Janie would have bumped into John-Paul Fitzpatrick at a house-warming party in Lane Cove, just moments before Cecilia Bell walked in the door.

None of us ever know all the possible courses our lives could have, and maybe should have, taken. It’s probably just as well. Some secrets are meant to stay secret forever. Just ask Pandora.