SNAPPER launches with a clever, meta-cinematic sequence at the Twilight Drive-In, 1975. As moviegoers settle in, two outrageous trailers flicker across the screen. The main feature begins as a group of young friends arrive at Turtle Lake for a long weekend of sun, booze, and romance, unaware of a young couple recently and gruesomely killed by something lurking beneath the water. Meanwhile, Sheriff Schwarz and Deputy Putnam investigate the mounting disappearances, uncovering a legacy of government cover-ups and environmental disaster. Edgar Black Crow, a local outcast, reveals the turtles’ origins: military experiments gone wrong, unleashing nature’s vengeance. The horror crescendos in a blood-soaked massacre at the public beach, where vacationers are slaughtered in scenes that echo the drive-in trailers’ gleeful excess. The authorities and survivors mount a desperate defense, but the turtles prove nearly unstoppable.