As the cream of world swimming limbers up for the world championships, explosive doping allegations against Chinese giant Sun Yang that refuse to go away could overshadow events in the pool.
Boasting unparallelled strength in depth, Americans are expected to dominate the medals once again with swimming glitterati Caeleb Dressel and Katie Ledecky leading their charge for gold in South Korea.
"It's all about racing now, about staying positive and really just rolling with it," Dressel told AFP.
"I've never been very public about goals but the point of this meet is really just getting your hand on the wall first."
However, the spectre of another damaging doping scandal looms after a leaked FINA doping panel report appeared to confirm rumours that the sport's pantomime villain smashed blood samples with a hammer after testers visited him last September.
Sun, a nine-time world champion and the only swimmer to win Olympic gold over 200m, 400m and 1,500 metres freestyle, clashed with rival Mack Horton at Rio in 2016 -- when the Australian labelled him a "drug cheat" over a prior three-month suspension for using a banned stimulant.
The bombshell revelations in the FINA report have stirred a hornet's nest likely to trigger more salty reaction from athletes when they bump into Sun over the next week.
"Hopefully there will be no problems," said FINA executive director Cornel Marculescu.
"It's difficult to say but I don't think it's going to have an influence on the swimmers."
After World Anti-Doping Agency (WADA) appealed to the Court of Arbitration for Sport, Sun faces a possible lifetime ban if found guilty at a hearing set to convene in September.
Any public row in Korea would further embarrass FINA at a world championships whose slogan "Dive into Peace" runs alongside posters of disgraced South Korean swimmer Park Tae-hwan -- who himself has served a lengthy doping ban.
- Peaty record bid -
Those not caught up in the storm enveloping swimming's enfant terrible will be looking to build confidence at these world championships in a dress rehearsal for the 2020 Tokyo Olympics.
"I feel really good about my preparation," Ledecky told AFP. "Let's see where we are against the best in the world so we can make adjustments going into 2020."
American swimmers plundered 18 gold, 10 silver and 10 bronze medals in 2017 with Britain (4-1-2) a distant second and Russia (3-3-4) third.
Dressel ruled the pool in Budapest, becoming only the second swimmer to capture seven gold medals at a single world championships after Michael Phelps achieved the feat in 2007.
The 100 metres butterfly title appears Dressel's to lose but the tattooed pin-up will find his 100m freestyle crown harder to cling to.
Olympic champion Kyle Chalmers looks a good bet in the men's blue riband event and some sizzling performances in the run-in that suggest he could even threaten Brazilian Cesar Cielo's 10-year-old world record of 46.91sec.
Australia flopped at the 2017 world championships, finishing eighth in the medal table but have brought a leaner, meaner team to Korea led by Chalmers and Cate Campbell, who is chasing a freestyle sprint double.
Swedish star Sarah Sjostrom, reigning world and Olympic champion in the 100m butterfly and world record holder over one and two laps of free, will have a say in the shake-down for medals.
Elsewhere, Britain's Adam Peaty takes aim at his own world record in the 100m breaststroke as he tries to extend a five-year unbeaten run over two laps in major competitions.
"The world record is my main motivation now," he said. "How to get below that magic 57 seconds."