Jason Baird receives a mechanical heart in a transplant, but it causes other body parts to develop into mechanical ones as well. He uses his new body to rescue two astronauts who crash-landed in Central America.
A comet's tail passes over a skyscraper, causing its elevator to pass into another dimension. The four people on the elevator, each a failure in some way, regain their confidence through their experiences in the other dimension when they return to Earth.