A group of firefighters in Vacaville, Calif., were treated to a nice surprise this weekend when they discovered that an anonymous woman had paid for their groceries.

While standing in line at a Costco store, the firefighters, who were wearing camouflage T-shirts in honor of Memorial Day, received an emergency call. When they returned to the store, they discovered that somebody had picked up the tab on their food, CBS Sacramento reports.

The kind-hearted woman didn't give her name, but she did leave a note on the $123 receipt that read, “Firefighters - Thanks for being there for us! Have a good weekend." She had signed it: "Air Force wife."

The firefighters didn't have a way to thank the woman, so they posted a note of appreciation on their department's Facebook page. They're also making an effort to pay it forward, according to CBS Sacramento.

“Later that day [Sunday] the crew was at Lucky’s,” Battalion Chief Jeff Ryder said. “There was an older couple behind them buying flowers [that] appeared to be for Memorial Day ... and the crew took some of that money and bought the flowers for them.”

The crew also plans to host a 90-year-old veteran for dinner at the station on Tuesday evening.

Ryder told CBS Sacramento that the gesture was especially poignant because it occurred on a day when people were honoring members of the military.

“This was special because it’s Memorial Day weekend, and it happened to be an Air Force wife that did this for us,” Ryder said.

Facebook commenters were clearly moved by the story. "That's what I like about Vacaville, it still has that small town heart and shows there's still good people out there," Mary Coursey wrote.

Carolyn Tipton Wold wrote, "What a wonderful woman. It is an awesome reminder that the world is filled with all kinds of people; some who strive only to hurt others and some, like this woman, who strive to spread kindness. God bless her and her family."

Follow Mike Krumboltz on Twitter (@mikekrumboltz)