Chicago schoolteacher Kimberly Bermudez has always been the chatty type.
So when she was on a Southwest Airlines flight to Florida to visit her parents last week, and her seatmate asked her what she did for a living, she told him about her first-graders, some of whom are homeless, and all of whom come from low-income families.
He asked her: "What's the most challenging part of your job?"
When children come to school hungry, she said, and seeing hard-working immigrant parents struggling to provide basic necessities for their families.
"You can't control what happens at home," Bermudez, 27, said in an interview with the Washington Post, recalling what she told him. "These parents are amazing. They won't eat to feed their child."
The seatmate replied that his company donates to schools such as hers, and she enthusiastically said her charter school, Carlos Fuentes Elementary, would welcome it.
All the teachers and administrators in the school dip into their own pockets to help the kids with whatever they need - underwear, soap, school supplies - because of how much they care, she said.
A moment later, she felt a tap on her shoulder. She turned around to see the man seated in the row behind her, who had a baby on his lap.
He apologised for eavesdropping. Then he handed her a stack of cash.
"Do something amazing," he told her.
Bermudez looked down and saw a $100 bill on top. She remembered from her babysitting days that her parents said never to count money in front of anybody. She accepted the gift and thanked him. She felt her eyes filling with tears.
"I said, 'You have no idea how much this means. Whether it's books or backpacks, I'll make sure I give something to the children,' " she said.
As the plane landed in Jacksonville, a man in the aisle across from her told her he was listening to her conversation as well.
He said he didn't have much money on him but handed her a US$20.
Then a third contributor: "As if my heart couldn't be any happier, the man in front turned around as well," Bermudez said.
He said all he had was US$10, and he gave it to her.
She began to cry in gratitude.
"I said, 'I'm not here to solicit money; I really am here on this plane just to see my parents," she recalled saying. "And one of them said, 'I know. That's why we're giving it to you. Use your voice. Use your gift of talking.' "
Bermudez walked off the plane almost in a daze. She had no idea how much money she was holding.
Her mother picked her up , and when she got in the car, she counted the money: Five US$100 bills, one US$20 bill and one US$10 bill.
She was holding US$530, all given to her by kind strangers, all to help the kids she loves.
Bermudez was not only shocked by the generosity of her fellow passengers but also surprised at something else.
"My generation, we don't carry any cash," she said. "I would never expect a complete stranger to have that much cash on them."
She posted her story on Facebook, where it has been liked by more than 1000 people and shared nearly 800 times. Some of her parents' friends saw the post and sent her supplies and books for her students.
Bermudez said she plans to use the money to buy books for her students, many of them emerging readers, so they can keep them at home. She also is looking into buying backpacks and other school supplies for her students.
As for the man who gave her the stack of hundred-dollar bills, he remains a mystery.
"I have no idea who he is," Bermudez said. "He was just an amazing stranger."