Like many survivors of the Holocaust, after World War II, Saul Dreier and Reuwen (“Ruby”) Sosnowicz moved to America, started families and careers, grew old, and retired to Florida. For these octogenarians, settling near Boca Raton could have been the last chapter in their story.

But then, last summer, Mr. Dreier, 89, decided to start a klezmer band, drawing upon the music he grew up with in Poland. Playing the drums, he teamed up with Mr. Sosnowicz, an 85-year-old Polish accordionist. This Op-Doc video profiles the two men and their group, which they’ve named the Holocaust Survivor Band. In recent months they have performed for audiences at venues ranging from local nursing homes and temples to The Venetian in Las Vegas.

Music has always been a tool of survival for these men. Mr. Dreier, the drummer, was born in Krakow and in his youth survived three concentration camps. In one, there was a cantor in his barracks. To pass the time, the boys formed a choir, singing soprano, tenor and baritone parts, switching as they grew up and their voices changed. Mr. Dreier learned to play drums by banging two spoons together as he accompanied the choir. Later, he worked as a construction contractor in New Jersey.

For Mr. Sosnowicz, music was recovery. He spent the war hidden by a Polish farmer, sleeping next to cows and digging through trash at night to collect bits of potatoes. After the war, he landed in a displaced persons camp in Germany, where he acquired his first accordion. Mr. Sosnowicz went on to become a hairdresser and professional musician. He played at parties throughout the borscht belt in upstate New York, and even had a gig at Studio 54.