It's a tragedy that can strike anyone, even a highly trained athlete: Spinal cord injury and paralysis. This summer Chinese gymnast Sang Lang fell while practicing for the Goodwill Games. She was paralyzed from the waist down, and doctors say she will probably not walk again. But researchers have made enormous strides in the area of spinal cord injury, and a cure no longer seems impossible. CBS News 48 Hours introduces you to some brave paralysis victims, including Christopher Reeve, and shows you the science that just may help them walk again. Among the people you'll meet: Christopher Reeve, the brave actor who three years ago was paralyzed after a horseback riding mishap. Reeve tells 48 Hours he still cries when he wakes up, mourning his lost mobility. Charley Hince, a charming, funny 26-year-old who two years ago broke his neck in a swimming accident. How does he deal with the enormous changes his condition has brought? And how will he pay for his enormously expensive care? Wise Young, a spinal cord researcher who thinks he may be very close to finding a way for people like Reeve and Hince to walk again.