VANCOUVER -- Annika Parkinson-Dow and her fiancé Colby Crockett have quite the tale to tell, and perhaps an eight-limbed helper to thank.

On Friday, the pair went for a swim at their neighbour's dock.

"It was pretty cold, but it was beautiful," Parkinson-Dow told CTV News. The couple was at their home on Bowyer Island, near Bowen Island, with their seven-month-old daughter, Isla.

That night, Parkinson-Dow woke up and noticed her engagement ring was not on her finger.

"She turned the room inside out," said Crockett.

The ring is a family heirloom. It was Crockett's grandmother's, later passed down to him. His grandmother got it in 1944.

So the next morning, Parkinson-Dow started reaching out to diving schools in Vancouver, hoping someone would search for the irreplaceable ring.

"I just sent a few emails out," she said. "But I didn't think they'd be open or answering emails on a Saturday morning, and because of the whole coronavirus thing, I didn't know if that was even a possibility."

Fortunately for her, someone did. And they arrived an hour later.

The search was not easy, though. Crockett said the two divers used an entire tank searching the bottom of the ocean by their dock for an hour and a half.

"They'd given up hope and they were actually swimming back to the ladder," he said, but then they spotted an octopus.

"They followed it for just, like, a couple seconds and then it led them to the ring."

"Pretty incredible," said Parkinson-Dow. "Apparently octopus actually like shiny things, from what I've heard."

Chris Harley, a zoologist at the University of British Columbia, said, "Octopuses do collect a variety of things to put in front of their dens, and sometimes these objects are a bit fancier than rocks and shells.

"Sea glass, bottle caps and other items have been found outside of octopus dens. So yes, it is possible that that the octopus found the lost ring and decided to use it as home decor, so to speak."

Harley said it's hard to say why the octopus would have led them to the ring.

"Of course, it could also have been a coincidence, but I love that an octopus was involved at all," he said.

The ring is now safely back on Parkinson-Dow's finger, and she's promised not to swim with it on again.

But there was one other serendipitous moment in their engagement story, Crockett said.

When he proposed to Parkinson-Dow, it happened near a humpback whale in the water by their dock. It turns out the two divers that helped them find the ring had whale tattoos.

"I do think his grandma was part of this: a guardian angel," said Parkinson-Dow.