Courtesy Felix Zabala

Miami Senior High School student Cristhian Reyes had his lost wallet returned by a total stranger with conditions attached, but not the kind of conditions Reyes was expecting.

Instead of asking for money in exchange for the wallet, the anonymous finder filled Reyes' wallet with $20 apparently added and a note that read, in part: "I added $20 to it so you know the world is a great place. Do me a favor and when you get the chance, do something nice for someone else."

The act of kindness was committed by the stranger last Friday, two days after Reyes, a high school senior, lost his wallet while attending opening day for the Florida Marlins.

Reyes had his high school ID, along with his driver's license and $60 cash, tucked inside his wallet. When the man found the wallet, the $60 apparently was gone but Reyes' high school ID was there - so the man brought the wallet, in an envelope along with the note, to Miami Senior High on Friday morning.

"I was passing by the office at the time and the secretary said, 'Zabala, look at this,'" said Miami Senior High School Vice Principal Felix Zabala. "I was in awe."

Zabala took a photo of the letter and emailed it to the entire staff, and broadcast the story to the entire student body as a lesson in kindness.

"I hope the students learn that you have to do good deeds in life, that it's important," Zabala said.

Reyes, who was in class and not available for comment, has already learned that lesson, according to Zabala, and plans to "pay it forward" as his anonymous benefactor requested.

"I imagine he would," Zabala said. "How can you not? How can anybody, if you're in the story, not want to do something like that?"

The man who found Reyes' wallet and brought it to the high school left without leaving his name and just, "rode off into the sunset," according to Zabala.

"A big thank you to this individual that's out there," Zabala said.