Nun, 105-years old, writes to prisoners to keep their hopes up.

Sister Mary Mark at her 105th birthday party.

Three parts of that headline would be unique on its own. Nun. 105-years old. Prisoners. Together, it's the likes of a short story you'll rarely come across.

Sister Mary Mark of St. Paul, Minnesota, celebrated her 105th birthday last month. And for over eighty of those years, Sister Mary Mark has written to a variety of men in correctional facilities around the country in hopes that it gives them encouragement.

"I surely do [enjoy] writing the letters and I've been doing it for many years," Sister Mary Mark told ABC News. "They're in prison, but they're working. They hope to make it."

Kathleen Conrad, who oversees the care at Carondelet Village in St. Paul where Sister Mary Mark lives, said motivations behind Sister's gesture are pretty simple.

"She says she just offers [the inmates] love and encouragement and let's them know that they're not alone," Conrad told ABC.

You're not alone. From an old woman in a nursing home to young men behind bars.