"I was out feeding the chickens. It's amazing how quickly it went."
The couple were alerted to the blaze by the barking of one of their dogs.
"It was too far gone for us to do anything," Mrs Lynn said.
"When we came out, the flames were coming out from the garage. Lots of black smoke. The flames were coming out the side."
She suspected the cause of the fire had been a ride-on lawn mower, which her husband had not long finished using and had returned to the shed.
"My husband panicked because it's his man cave. Everything is gone."
Mrs Lynn said her grandfather's "irreplaceable" tools had also been in the shed.
"There was petrol and plastic containers exploding - that was pretty scary."
The fire had spread to a neighbouring barn and trees up the hillside.
"It was just so dry," she said.
"I was just so thankful the totara didn't catch. Garage you can replace but that you can't."
Mrs Lynn called the fire department "at 5.41 and they got here at 5.52".
Looking on the bright side of things, the fire "might have nailed the rats.
"Sad we lost the quad. We'll have to walk up to water the cows, or take the truck up.
"I will just keep thinking about the good things - we're all okay."
Featherston Fire Chief Colin McKenna said the shed was burned to the ground.
"There was a lot of smoke. Smoke everywhere in town."
The Lake Ferry Rural Fire Force had been called to the blaze as the fire had spread from the structure to the trees.
He said it had taken about an hour-and-a-half to extinguish the fire.
"There was another big open shed arrangement. It burned a bit of that but didn't do too much damage but the shed itself was on fire, it burned to the ground.
"There was petrol stored in there for the quad and ride-on lawn mower so all that stuff only helped burn it down, that's for sure."
Mr McKenna said the Featherston fire crew left when the fire was out, but the Lake Ferry crew had stayed on as a precaution.