What began as a sail around the world and turned into a love story ended in tragedy when one man's crewmate-turned-wife suddenly died in his arms one night.
Sylvia Fink's autopsy was inconclusive, but her husband Doug says it was a "miracle cure" that suddenly took her life.
Doug said his wife consumed Miracle Mineral Solutions (MMS), a remedy that claims it can be used to overcome "most diseases known to mankind" including cancer and HIV, just 12 hours before she died.
It is also advertised as a preventative for malaria, which Sylvia had wanted to protect herself from when she and Doug arrived at the Vanuatu Islands in 2009.
Sylvia, 56, had wanted to avoid the malaria pills she took once before and met fellow sailors who sold her the MMS mixture.
"She thought it was a valid medicine," Doug told ABC's 20/20. "'Turned out, it wasn't."
Only 15 minutes past before Sylvia began to feel terrible. And as the day went on she suffered diarrhoea, nausea and began to vomit.
But the solution's packaging said these symptoms were normal and even proof that the MMS mixture is working, so Sylvia wasn't worried - at first.
"It got worse and worse," Doug said. "And by mid-afternoon she was in...lot of pain.
"By evening she was starting to be serious. And by this time I realised she was suffering from poison."
Doug called for help on their boat's radio, but it was too late.
Sylvia became limp in his arms and her eyes rolled back.
"That'll haunt me for the rest of my life," Doug said. "The vision of her face, just inches away from mine, and those eyes suddenly de-focusing."
A nurse tried to revive her, giving Sylvia a shot of adrenaline, but nothing worked.
"There's no point," the nurse told Doug. "She's gone."
It was a devastating end to a magical love story.
Sylvia had been Doug's crewmate when he first set sail for his trip around the world in 2004.
Within six months into the trip, the two knew they had something special.
They eventually got married, living happily as husband and wife as they travelled through South America and spent two years in New Zealand before stopping in the Vanuatu islands.
The night before she died, Sylvia was dancing with the local children in the village. Doug said she was as healthy as could be at the time.
"There's no doubt in my mind," he said. "MMS did kill my wife."
A local hospital later found that Sylvia had a "concentrated solution" of sodium chlorite in her system at the time of her death.
The chemical compound, which is generally used for bleaching purposes, is also the main ingredient in MMS.
"They might as well be selling Clorox," said Ben Mizer of the US Department of Justice.
"You don't drink Clorox, so there is no reason you should drink MMS."
Doug filed a report against Project Greenlife, a Nevada-based company that sold the MMS bottles Sylvia had bought, with the US FDA in 2011.
Four years later, Project Greenlife manager Louis Daniel Smith was sentenced to more than four years in prison for "marketing a toxic chemical as a miracle cure".
"The verdict demonstrates that the Department of Justice will prosecute those who sell dangerous chemicals as miracle cures to sick people and their desperate loved ones," said Mizer.
New Zealand's medical regulatory body, Medsafe, says the product is nothing more than industrial bleach that can cause "serious harm to health".
But the MMS industry continues to this day, thanks to the Genesis II Church of Health and Healing, which is working hard to dispute negative publicity about its product.
The church, which was founded around 2010, continues to claim that thousands of people have been cured because of MMS.
Now Doug is fighting against the church, hoping others won't be seduced by the promises of MMS and experience his same pain.
"Don't do it, because it may harm you," he said.
"It harmed me greatly by causing my lover and my life and my partner in sailing to no longer be with me."