Melanie Agnanos’ Nightswimming opens in the early hours of a cold January night in Paterson, New Jersey, in 1979. Owner Randall Low is closing up RJ’s Taproom, a bar and strip club serving a working-class clientele in a city that’s a few decades past its heyday. Dancer Cindy Kaczorek stands with him behind the bar when an unexpected visitor arrives. Hours later, a friend finds Danny’s and Cindy’s bodies in a pool of blood by the register.