Running out of petrol is never a nice experience. Running out of petrol on a motorway in the middle of the night is even worse.
When it happened to Kate McClure, on the outskirts of Philadelphia in the USA, she said her heart was "beating out of her chest."
She pulled her car over and got out to try and walk to a petrol station, but before she could she was approached by a heavily bearded homeless man.
It sounds like the story is about to get scarier, doesn't it? Luckily, something incredible happened. The man told Kate to get back in her car and lock the doors.
Twenty minutes later, he was back, bearing a full petrol can that he'd spent his last $20 (about £15) on.
His name was Johnny Bobbitt Jr, and he wouldn't take Kate's offer of repayment, saying all he wanted was to make sure she was able to get home safely - but Kate had other ideas.
Over the next several weeks she would stop by the section of motorway Johnny regularly stayed at, giving him small gifts of water, cereal bars and some cash, to help him through the days.
But as winter approached, Kate wanted to do more. She set up a GoFundMe page telling her story, saying: "With the money, I would like to get him first and last month’s rent at an apartment, a reliable vehicle, and 4-6 months worth of expenses.
His life can get back to being normal.
"He is very interested in finding a job, and I believe that with a place to be able to clean up every night and get a good night’s rest, his life can get back to being normal."
Johnny was previously a US Marine and also has a background in firefighting, but had fallen on hard times.
The story caught the attention of the whole country, and within days had raced past the goal of $10,000.
And at the time of writing, it had reached an incredible $289,000 in under two weeks.
Kate shared a video of the moment she told Johnny about the fundraiser, with the veteran fighting back tears.
In the post's most recent update, Kate wrote about how Johnny wanted to use the money raised to help others, paying forward the good deed that Kate had started.
So the heartwarming story may yet have several more happy endings!