Waldorf's owner, too, seemed to have disappeared.
But Ms Stott decided to keep trying to find the owner rather than hand the friendly dog over to the authorities.
She contacted Auckland Council and learned Waldorf had gone missing three years ago, with his owner unsuccessfully advertising for months for his return.
She also put photos on social media and wrote: "If you can tell me the dog's name (it's on the vet file) and the sex I'll happily return this beautiful one to you."
Meanwhile, Auckland Council had traced the registered owner's friend whose details were also registered on the microchip.
Ms Stott then heard from Mr Li who was ecstatic to get the news Waldorf was alive and well although, mysteriously, 160 kilometres away.
"He said, 'do you have Waldorf?' I said, yes. He said, 'do you really?'. He couldn't believe it. He was surprised, shocked, thrilled."
The owner was currently in China but Mr Li said he would look after Waldorf until his return.
On Saturday morning he travelled to Whangarei to collect the dog that was not quite a year old when he went missing after a real estate agent left a gate open.
After all that time, as soon as Waldorf saw Mr Li, he started whimpering and ran straight to him, Ms Stott said.
"They were so happy to see each other."
Ms Stott said the tale showed the value of owners getting their pets microchipped. Her social media call had also drawn offers from people wanting to adopt the rottweiler.
"I did think at first, 'what am I going to do with this dog? How am I going to explain him to the landlord?' It's definitely the best ending to a story I could have hoped for."