It could almost be the plot of a classic festive film: a kind gesture from a mysterious stranger who vanishes before being thanked.
But after one man's 'uplifting' generosity in paying for their Christmas meal, a group of Norwich nurses are now hoping to express their gratitude to him.
Sarah Knights was enjoying dinner with three friends at the Vine Thai, on Dove Street, when a stranger stepped in to pay for the group's meals and drinks.
And now she is trying to track him down to pass on their appreciation.
Mrs Knights, 30, from Norwich, said: 'We were sat finishing our food and drinks and just chatting.
'This man who was sat at the bar asked what we did, and when we said we were nurses he offered to get us a drink.
'We had to say no as we were all working the next day, or driving but when we went to get our bill the lady said it had been paid for and pointed to him.'
Mrs Knights, a primary care nurse, said the group were taken aback and 'really surprised' at the kindness.
She said: 'It was £80-odd pounds and we couldn't believe it.
'We went up and thanked him and asked why, and he said someone in his family had had cancer, and said 'you help people'.
'I think it was his grandad.'
She added: 'It was so sweet, but he got a bit embarrassed because people were looking and could hear, and just turned back around.
'We kind of walked out because we were still in shock but I was driving home and I thought that's just ridiculously kind.
'I just felt in the moment we didn't really get a chance to thank him properly.'
Mrs Knights messaged the restaurant, hoping to contact the man, who had been there alone.
'I got in touch and they said he had left already and wasn't a regular customer,' she said.
'Even if he just sees this - you're a really kind man and it wasn't a proper thank you.
'It was such an uplifting, festive thing to do.'
Mrs Knights said she and her friends - A&E assistant Jo Kluczykowska, 25; mental health nurse, Joy Eglington, 24; and her sister-in-law intensive care nurse Nancy Eglington, 28 - all trained together in nursing at the University of East Anglia (UEA).
She said: 'He was absolutely charming, a total gentleman and talked fondly about his girlfriend.
'I didn't get his name though.
'He was wearing dark blue jeans and a quilted blue jacket with blond hair - and he was 32.
'He said he had a business to do with wind farms off-shore.'
The group ate Thai green curries, spring rolls and crispy chilli beef, and drank wine, beer and soft drinks.
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