“Donnie and Fran are a street version of Cinderella and Prince Charming, but when they fell in love they didn’t have any magical dust in their eyes,” said the Rev. Frank M. Reid III, pastor of the Bethel A.M.E. Church here, who will perform the ceremony. “They also show us something about salvation, since now they’re using their skills from the corner to pull other people through.”

When Mr. Andrews and Ms. Boyd met more than 10 years ago, each was a prisoner — although only one was behind bars — and each began helping the other get free. Ms. Boyd, 50, has been clean for more than 10 years, in large measure, she says, because Mr. Andrews, 53, saw her through the worst times, using all he earned in the prison factory to make daily calls to her. When another man was living with her, when she was too high to make sense, when she screamed at him to stop calling, he called anyway, all the while gently nudging her to get her life back.

“Yeah, she put on a routine, being all tough,” said Mr. Andrews, his 6-foot-1, 230-pound frame enveloping the 5-foot-4 Ms. Boyd in a bear hug. “But who was home every single day waiting by that phone at 4 p.m.?”

The first time they saw photos of each other was two years into their relationship. “By that time, it was too late for us,” said Ms. Boyd, who was introduced to Mr. Andrews over the phone by the police officer who arrested him.

Ms. Boyd spends her days now walking her old haunts, persuading addicts to go into rehab and working with a local hospital’s H.I.V. prevention program, when she is not home raising the three nephews and nieces she rescued from their troubled home.