Rollercoaster

An unnamed young extortionist (Timothy Bottoms) sets off a bomb on an amusement park roller coaster, causing multiple fatalities, then says that he will do the same to five other rides around the country simultaneously unless he's paid one million dollars. Amusement park employee Harry Calder (George Segal) gets unwillingly drawn into the precarious situation when the FBI's lead agent (Richard Widmark) presses him into service as the go-between with the authorities and the bomber.