It all happened so fast. One moment Kevin Stephan was washing dishes at his part-time job at the Hillview Restaurant in Depew, N.Y. The next, the high school senior was performing the Heimlich maneuver on a diner choking on a piece of beef. Two quick thrusts later, the piece of meat flew out, and the woman was breathing. Only then did Kevin's mother, Lorraine—at the restaurant for lunch—tell her son whom he had rescued: Penny Brown, 44, the woman who had saved Kevin's own life after a terrible baseball accident seven years earlier. "It's like divine intervention," says Kevin, 17.

Or incredible good fortune, anyway. In July 1999 Brown—an intensive-care nurse—got an unexpected night off and was able to attend her son's Little League baseball game. During the game, she watched in horror as Kevin, then 11 and a batboy, fell face first into the dirt after being hit in the chest with a baseball bat. Rushing down from the stands as Kevin's terrified parents looked on, Brown pounded Kevin's chest and, getting no response, started CPR. Kevin came to.

As he grew up, Kevin honed his own first-aid skills, first as a Boy Scout and then as a junior firefighter for Bowmansville's volunteer department. Now—busy with college applications and plans to continue as a firefighter, the third generation in his family—he dismisses talk of being a hero. But Brown says all the attention is well-deserved. "This," she says, "is an experience neither of us will ever forget."