Katarina Johnson-Thompson's sliding doors moment came courtesy of south Liverpool's bus network.
Then aged 10, she used to hop aboard to travel the six miles from her home in Halewood to Liverpool Harriers' base in Wavertree Park.
She headed there as a high jumper. Her talent was obvious - tall and agile, she had broken a 29-year-old school record at her first attempt.
Her mother Tracey, who would have preferred her daughter to dance, sat reluctantly alongside her, riding routes through south Liverpool's suburbs.
The high jump session lasted 60 minutes. Not a lot longer than it took to get there. It seemed a hassle for only an hour.
But if Katarina stuck around for the running session that followed the high jump, maybe it was worth the trip after all.
When she did and proved she could sprint as well as she could leap, a coach mentioned an event that combined them all. Johnson-Thompson's path was set.
Although Katarina and Tracey didn't realise it then, that bus ride was only the beginning of the journey.
Aged 13 she took a National Express coach down to Stoke for her first age-grade national championship.
By 19, she was riding a wave of national emotion instead, appearing as Jessica Ennis-Hill's heir apparent at London 2012.
It was a steep and rapid rise.
"I was one of the first athletes on the track - the heptathlon was on the first day," Johnson-Thompson tells BBC Sport. "I was used to competing with 40 people and there were 80,000 people screaming for anyone in Team GB.
"I was actually shaking as I was so excited. I was absolutely loving life; there was zero expectation."
That changed. The pace of progress slowed to nearer normal. But the hype and expectation did not.
"With Jess taking time out to have her first child, everyone was still watching the event but the star wasn't there. I thought I had to step in to fill those shoes," remembers Johnson-Thompson.
"I don't think I had those transitional years. I just got thrown into the deep end and I think 2015 and 2016 in particular were those two years where I just couldn't handle it."
At the World Championships in Beijing in 2015, she fouled on each of her three long jumps, wrecking any hope of medal. After that disappointment, she changed her screensaver to a shot of her foot straying beyond the take-off board. It was a daily reminder to spur herself to better.
A year later, though, she arrived at the Olympics in Rio mentally and physically spent. A quad tear and knee surgery fuelled her demons and self-doubt and she finished sixth.
"If I did a bad throw I would wonder what the commentators were saying - I bet they are ripping into me," she says.
"It was this really toxic negative voice I would always have talking to myself when I was competing.
"I think I believed a lot of people who were saying these things. It got to that point I thought 'am I a heptathlete'?
"That victory lap in Rio was the third consecutive year where I was doing the same thing and getting the same results."
Things had stalled. Something had to change.
There was a safe option. To stay at home, 10 minutes from Tracey, with the same coach she had had since she was 15. Maybe she could shift to specialising in the high jump. It would be a return to the very beginning.
The other option was a swerve into the unknown.
If Katarina is a self-confessed 'homebird', Tracey flew the nest early. As a teenager, she left England alone in the early 1980s to travel to Paris, looking for work at the famous Moulin Rouge nightclub.
"My mum was a show girl, a dancer in the can-can," says Johnson-Thompson.
"She travelled the world from a very young age. It is not like it was now where you can stay in touch with people. She left home and she had to write letters to my nan."
And in November 2016, daughter followed mother, packing her bags for France, sensing her dreams couldn't be fulfilled at home.
She rented a small flat in Montpellier, deep in the south of the country and threw her lot in with coach Jean-Yves Cochand.
He changed her training and her technique from the ground up. New run-ups for the jumps, new body angles on the throws, a new emphasis on strength in the sprints. A shift to little and often, with Johnson-Thompson moving away from a mix of heavy sessions and rest days.
But most importantly he and fellow coaches Bertrand Valcin and Bruno Gajer changed her mindset.
Cochand revealed to Johnson-Thompson that he had nicknamed her 'Droopy' on account of her hangdog demeanour in competition. And it had to change.
Johnson-Thompson didn't speak French, but she quickly caught on to the meaning of 'C'est la vie'
"Bertrand is my coach now. He is chilled in competition and that chills me out when I see him chilled," she says.
"My training partner Kevin Meyer, a French decathlete, has a really, really strong mindset too. He came to Berlin for the European Championships in 2018 as the world champion, but did three fouls in the long jump [the same error Johnson-Thompson made in Beijing in 2015].
"He came to the cameras, shrugged and said: 'It's sport. I wanted to give my best performance on the day and that meant that these things happen.'
"Two months later he went out and broke the decathlon world record and it is forgotten about.
"Whereas for me, I went into hiding, I went into my mum's hotel and was crying all night.
"I'd be punishing myself for it all the time. Up until 2018 or 2019 every time I'd get on a long jump runway I'd think about that.
"I knew leaving Liverpool was necessary - and my mum did as well - for me to get to where I wanted to get to."
Heading to the 2019 World Championships in Doha, there was neither the fizzing excitement of 2012 nor the doom and dread of 2016 for Johnson-Thompson, just an acceptance of self and that what would be would be.
"I was ready to go and I was ready to lose as well," she says.
"I didn't feel any sort of expectation to get a medal because I just knew I was in a good shape to do a good score, and I knew I was going to do it regardless of anybody else's score."
Johnson-Thompson upset the defending champion and Olympic gold medallist Nafissatou Thiam of Belgium to stand on top of the world, looking down on the doubters.
"The main emotion was relief - that I have got this now and if everything else fails I've got this," she says.
"There's been lots of times when I didn't believe and I went away believing other people's opinions."
From there, it seemed like a smooth, straight road to Tokyo and the biggest stage of all. The Olympic heptathlon was due to start 10 months and a day after she took world gold.
But then… events. A global pandemic shunted the Games back a year. And then, in late December 2020, Johnson-Thompson ruptured her Achilles tendon. Worse it was her take-off foot, the one that bears extreme load and complete trust when she competes in the long jump and high jump.
The injury nearly derailed her entirely.
"I was devastated and at one point it could have gone one of two ways but I'm glad it went in the best direction for me," she says.
"It has been a long and tough road, but I am glad I am at the other end of it."
She has a different screensaver now to help her find her way. It's from Liverpool, four miles from where that bus journey ended and her own began.
It's of Liverpool football team, her team, celebrating in front of the Kop, having pulled off a comeback for the ages against Barcelona.
"I take huge inspiration from Liverpool, to know that comebacks like that are possible and never to write anyone off," she says.
She comes into the Olympics under-cooked, but also potentially underestimated. That magical, mystery tour that started in Halewood could yet end on the top step of the Tokyo podium.
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