“No.” He would slow her down. She was running for the door to the garage. “No. Better stay here.”

“Don’t you drive too fast! Lyn, are you listening to me? You drive carefully, for Christ’s sake! You promise me? Promise me!”

The fear and frustration in his voice made her stop for a second and look at him calmly. “I promise. Don’t worry.”

“You three girls,” he called after her, as she ran down the stairs, her car keys held out in front of her like a sword, ready to push the button to deactivate the alarm, “You are so bloody, bloody…!”

“I know,” she called back, comfortingly. “I know.”

She prayed he didn’t hear the screech of tires as she accelerated out of the garage.

According to family folklore, swapping identities was a game Cat first played when they were just two years old and she was caught by her parents in the act of creating her own crayon Picasso on the living room wall.

Maxine and Frank exploded as one, “Naughty girl, Cat!”

Cat turned her head, red crayon artistically in hand, and realized from the identical expressions of horror on her parents’ faces that she had committed a terrible crime.

“Me Lyn,” she said craftily. “Not Cat.”

And for just a split second they both believed it was Lyn, until Frank lifted her up by the strap of her overalls for a closer look at Cat’s evil little sparky face.

When they were in primary school, the two of them regularly swapped classes, just for the sheer pleasure of conning their teachers. Lyn found it strangely exhilarating being naughty Cat Kettle, talking to the bad boys up at the back of the classroom and not listening to the teacher. In fact, she found it so easy and natural being Cat that when they went back to their own classrooms, she sometimes wondered if now she was just pretending to be Lyn. (And if she was pretending to be Lyn, she wondered, was there another Lyn—the real Lyn—deep down inside?)

When they turned sixteen the Kettle girls made the pleasing discovery that boys liked them, quite a lot. One night, Cat accidentally agreed to go out with two different boys on the same night. She only realized at the very last possible minute when one boy arrived to pick her up. The other boy was due to meet her at the movies in twenty minutes’ time.

It was a thrilling mix-up, with Cat dramatically clapping her hand to her mouth, her eyes wide with the wonderful horror of it. They all fell about smothering whoops of laughter in Cat’s bedroom, while the poor boy made strained conversation with Maxine. The only solution was for Lyn to go meet the other boy, Jason, at the movies.

Lyn went off to the movies feeling pleasantly frightened, like she was on a covert mission to save the world. It was only when she saw Jason leaning against a wall outside Hoyts, chewing nervously on the tickets that he’d already bought, his face lighting up when he saw her, that she suddenly felt awful.

“Hi, Cat,” said Jason.

“Hi, Jason,” said Lyn, and remembered not to apologize for being late.

It all went well in the beginning. They saw Terminator and Lyn avoided giveaway girly gasps, instead grunting with satisfaction at the most violent bits. At one stage she did worry she might have overdone it—she was laughing raucously at Arnie pulling out his eyeball, when she noticed that Jason had turned his head to look at her. But when she said, “What?” he grinned and pretended a piece of popcorn was his eyeball and ate it, so that was O.K., although revolting.

It wasn’t until afterward, when they were standing outside the movies, that everything went horribly wrong.

Suddenly, without warning, he leaned forward and kissed her, slithering his tongue weirdly along her gums. It was horrible, disgusting, mortifying. It was like being at the dentist with your mouth forced agape and unexpected violations with strange instruments and excessive saliva buildup.

When he’d finally finished with her mouth and Lyn was feeling an urgent desire to gargle and spit, he stood back, narrowed his eyes, and said, “Are you Lyn? Are you Cat’s sister Lyn?”

She tried to explain, but he was squaring his shoulders and squinting his eyes with cold contempt, just like the Terminator. “You Kettle girls are bitches, prick teasers,” he said. “And you, you can’t kiss.” Then he delivered his final, devastating blow: “’Cos you’re frigid!”

Lyn went home on her own, disgraced, humiliated, and…frigid.

She told Cat and Gemma that they’d been caught, but she never told them about the absolute confirmation of her worst secret fears. All she said was, “I will never, ever do that again.”

She was too late.

The flashing blue lights were visible from a block away, illuminating the little group of people, policemen, cars, and tow trucks in ghastly turquoise, like a stage set for a play.

As she pulled over, her own headlights shone a spotlight on the sickening, crumpled, caved-in side of Cat’s precious car. It was a proper accident. The idiot could have killed herself.

The reality of it was shocking. Now she wished she’d let Michael come with her.

She parked her car and walked toward the circle of people. Cat was in the center, all eyes upon her as she blew into a little white tube held by a policeman who looked like a teenage boy.

As Lyn approached she heard him say in a somber tone, “I’m afraid your reading is well over the limit.”

“Oh well.” Cat kicked at the ground.

A woman said to the man standing next to her, “I told you she was drunk!”

“Good for you, Laura.” The man shoved his hands into his jeans and frowned.

Lyn fought the desire to say saying something crushing to Laura-the-bitch and walked straight up to the policeman.

“Hello, I’m Lyn Kettle,” she said, in her bright but stern working-day voice. “I’m her sister.”

The policeman looked at her and seemed to drop his own working-day tone. “Gee, you can really tell you’re sisters! People must get you mixed up all the time.”

“Yes, ha! They do sometimes.” Lyn smoothed down her hair uneasily and hoped he wasn’t trained to pick up guilty body language. “Um. What happens now?”

The policeman switched back to his somber voice of authority. “Well, your sister will have to come down to the station with us. I’m afraid she’s likely to be charged with negligent driving and driving under the influence.”