The first thing you need to know about “Radium Girls,” Hood River Valley High School’s spring play, is that it’s based on a true story. And it is heartbreaking.

The Radium Girls, as they became known, contracted radiation poisoning from painting watch dials with self-luminous paint for the U.S. Radium Corporation. When the company refused to take responsibility for the women’s condition — they began to experience anemia, bone fractures and necrosis of the jaw — five sued and eventually settled out of court, though not all of them lived to see the result.