It was during one of those glorious days, as they skied back down to the resort, that they both took a heavy fall. Without even thinking about it, they’d decided to descend the slope while listening to a Walkman, sharing the same pair of earphones. Valérie had forgotten to bring hers. They loved listening to music while they skied, and they wanted to descend to the sound of the Pixies song, ‘Where Is My Mind?’. Obviously it was dangerous, but they were excellent skiers, and the piste that led down to the resort was a relatively easy blue run. They enjoyed skiing like that, with their skis close together and their heads leaning in to share the same song. But all it had taken was a small bump and one of them had been jolted sideways, their skis had crossed, their legs had tangled, and they’d both been taken down in a violent fall. Stéphanie began howling with pain, while Valérie was unscathed. The emergency services arrived pretty quickly and the injured girl was taken down to the resort on a sledge. An ambulance transported her to the hospital in Chambéry. The X-rays revealed a double fracture of her tibia. For two hours, Stéphanie brooded anxiously on a trolley in a hospital corridor, with no news of her sister. This was before the era of mobile phones. Valérie, meanwhile, was at the resort, trying to find out what had happened to her sister, and when she was told that Stéphanie was at the hospital she caught a bus there. Together again, they hugged. Her sister’s injuries weren’t really so bad, Valérie thought; she seemed more shaken than anything. But of course it meant the end of Stéphanie’s holiday. The next day, she would travel back to Paris, accompanied by Madeleine, who had left work in the middle of the day and caught the next flight to see her daughter.

Valérie stayed for the second week of the holiday and made some new friends. It was sad, but it wasn’t a big deal. The two sisters talked on the phone and Stéphanie told her: ‘Have fun for me.’ All the same, she couldn’t help wondering: ‘Why me and not her?’ There was no anger in this thought, it was simply an observation that a single act had led to two radically different outcomes. Bedridden and bored, she kept brooding on the situation, while Valérie continued hurtling down ski slopes. Fate had favoured her sister. The same question kept repeating on a loop – ‘Why me and not her?’ – like an annoying tune she couldn’t get out of her head.

Something else needs to be mentioned here. Taking advantage of the fact she was alone, Valérie grew closer to Malik, the young ski instructor on whom both sisters had a crush. At the last-night party, Malik couldn’t help noticing the way Valérie kept staring adoringly at him. After a few drinks, he ended up kissing her in a dark corner, before remembering how young she was and realising this was not a good idea. He made his excuses and left then, but the kiss – however brief – had really happened. Naturally, Valérie told her sister all about it, unaware of how deeply the information would affect her. For Stéphanie, it felt like salt rubbed in her wounds. For an instant she even wondered if Valérie had planned the whole thing. Had she caused the accident to get rid of Stéphanie, leaving the coast clear for her to get what she wanted? Perhaps the painkillers she was taking were fogging her brain, but in any case it was probably at that moment that she started to resent her sister.

While the two of them appeared outwardly as close as ever, Stéphanie had begun to mistrust Valérie. She no longer shared all the secrets of her private life with her sister, and now and then she would arrange to go out without telling her. Valérie was surprised by this, but it wasn’t so strange after all; they weren’t obliged to do everything together. The following year, when the ski season came round again, Stéphanie decided to go to the mountains with one of her friends instead. It was the first time they’d gone skiing separately. Valérie could not understand this decision. Particularly since it would have been easy enough to invite Valérie to go with them. But it was what it was. She must still be traumatised by the accident, Valérie thought, and the idea of skiing together would just bring back painful memories. But Stéphanie didn’t talk about any of that; she was just happy to be invited to join the family of one of her friends. She smiled as she ended their sibling ritual.

And so it went on. More and more frequently, Stéphanie would plan to do things without her sister. Cinema visits, shopping trips, parties. Valérie couldn’t help but think: ‘It’s not like it was before.’ This made her sad, but she didn’t dare mention it. Why should she make the first move when her sister didn’t want to be with her? She had no idea that the annoying tune was still stuck in Stéphanie’s head: ‘Why me and not her? Why me and not her?’ And things didn’t get any better. After the Malik episode, there was another boy problem. For a few weeks, Valérie had been going out with Benoît, a slightly older boy who played in a rock band. It was a cliché, of course, a seventeen-year-old girl hung up on a guitar hero. But that didn’t make it hurt any less when he didn’t call her for a week. She was deep in the throes of first love. She sought comfort from her sister, but Stéphanie seemed incapable of uttering a single word. Her look said: ‘You’ve got a cool boyfriend and I’m alone. Do you really expect me to console you when he goes off somewhere?’ There could be no doubt about it now: Valérie’s sister was jealous. It was the kind of jealousy that murders all kind feelings. For Stéphanie, the episode with Benoît had been just like that fateful ski trip. They’d met him together at a rock concert, but he’d preferred Valérie. Whenever they were side by side, she was always the one who stumbled.

In her paranoia, Stéphanie would sometimes think: my sister is a shadow cast over my future, a thief of possibilities. She is the one preventing me from living the life I want to live.

So often, children from the same family are compared. Which is absurd: just because you have the same upbringing does not mean you will have the same abilities or the same aspirations. Naturally, a child’s early years are crucial for their development, but their own choices play an even greater part: how many chaotic lives have come from cosseted childhoods? How many brilliant achievements have arisen out of abusive infancies? Stéphanie knew all this; she shouldn’t have let herself get caught in this futile competition. Especially since she kept losing. After the ski episode and the rock star episode came the most important of all: exams. It was the most important because, unfortunately, exams are how our society measures a person’s capacities, at least during the early stages of life.

After passing her baccalauréat, Stéphanie had failed the entrance exam for Sciences-Po. There was nothing too tragic about this, except that, the following year, Valérie’s application was accepted. Everyone in the family was thrilled and they opened a bottle of champagne to celebrate, even though nothing had been settled at that point: she still hadn’t taken her oral exam. For Stéphanie, this glorification of Valérie’s achievement just underlined her own failure. She continued down the road of this endless comparison. It was all the more ludicrous since the grades she was getting in her History degree were excellent. But her ego had been wounded and she seemed powerless to stop the spread of the narcissistic gangrene with each new insult to her pride. It is difficult to measure the amount of bitterness inside any soul.

There came a day, however, when her bitterness grew out of all proportion. Valérie was awaiting a letter announcing the date of her oral exam, but nothing came. This was before the internet existed, when it wasn’t always easy to obtain information. In the end, she went to the university’s administration office and was told that the orals had already taken place. She collapsed in sobs right there in the office, but it made no difference: she would not be able to join Sciences-Po that year. She had missed the second part of the exam, and that had ruined her chances. ‘I didn’t receive the letter!’ she protested to the secretary who, seeing her so upset, felt sorry for her. The secretary explained that all the letters had been sent by registered post with a signature required on delivery. She checked in a file that Valérie’s letter had not been returned, which proved that someone had received it on her behalf. Valérie thought instantly of her sister. So, somewhere deep inside, she had sensed the insidious vibrations of Stéphanie’s jealousy. She couldn’t simply accuse her, however. Stéphanie would deny it, she would act offended, she would make herself the victim: how could her own sister possibly believe her capable of such an act? Besides, there was no way of proving her guilt.

The family asked their neighbours and the building’s concierge if any of them had signed for the letter, but their investigation hit a dead end. There was no trace of the letter anywhere. In the end, Stéphanie said to her sister: ‘I can see that you think it was me. You can’t imagine how hurtful that is.’