An elderly couple from Gloucester have forgotten where they parked their car, following a visit to Cheltenham Hospital.
They have offered £100 reward to anyone who can help locate the vehicle - a Ford Fiesta.
Relatives and friends have spent four days scouring streets across the city, with no luck.
The car was parked "within a mile and a half" of Cheltenham General Hospital on Friday, but Emmanuel Elliott, 81, and partner Hilda Farmer, 79, cannot recall precisely where.
Mr Elliott described the street where the car was parked. It had "really nice houses on one side and some kind of greenery on the other".
"Frightened of Cheltenham"
Ms Farmer dropped Mr Elliot off at the hospital before finding somewhere to park.
"I don't know Cheltenham very well at all. I was born in Gloucester," she said.
"I'm frightened of Cheltenham. I [normally] always go on the bus."
The Ford Fiesta in question is silver and has the registration EJ12 VSP.
Mr Elliot described where his partner parked the car: "There were houses just on one side, and all the cars were parked in their driveways.
"On the other side there was greenery - maybe a park or a field.
"Ours was the only car parked on that side of the road, alongside the greenery."
Ms Farmer took around 30 minutes to reach the hospital on foot, so it was probably "within a mile and half", according to Mr Elliot.
Police said they are "fairly confident" the car will still be where they left it, he added.