Jacinda Ardern tried to hunt down a Hamilton-based violin repairman who swindled her grandmother out of a family heirloom.
The Labour leader revealed details of the unfortunate tale during an intimate interview with Newshub's Ryan Bridge at her Auckland home.
The story starts with Arden's great-grandmother migrating from Scotland to New Zealand armed with two precious possessions: a violin and a pistol.
Yes, a pistol - Jacinda Ardern's great-granny was an OG.
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"She was traveling on her own - so maybe it was [for protection] but it could well have just been a family heirloom. It's pretty old," she said.
But it's the story of that violin, hand-made by a student of one of Edinburgh's master violin-makers, that's done the most damage.
The violin was passed down to her nana, Gladys Ardern, and eventually to Jacinda herself, who played the instrument in her younger years.
"When I got a bit older I went to get it repaired and they asked me the story of it and I told them the age and they said the case fits the age, but not the violin," Ardern said.
It was then that Ardern learned her nana had been swindled by a violin repairman who went door-to-door offering to fix the old string instruments.
"As it turns out there was someone who was doing a trade in swapping violins in those days and my nana was sadly the victim of that. This is not the original violin but it is the original case."
Feeling angry and wronged, Ardern tried to track down the swindler but was told he had since passed away.
"What upsets me the most about that is that my grandmother was the kind of person who would never be swindled," she said.
She takes comfort from the fact her nana never knew the violin had been stolen and replaced with a much newer version.
You can watch Ryan's full interview with Jacinda as part of our 'At Home with the Leaders' series when it goes live at newshub.co.nz from 9pm tonight.