Wavelength (1983)

"Two weeks ago they landed on Earth. Today, beneath a major American city, the experiments begin..."

Plot Summary

Two young lovers learn that a small group of child-like space aliens are marooned on Earth and are being held prisoner at a top secret military facility. The couple then decide to liberate the extraterrestrial castaways and help them make a rendezvous with a rescue ship sent from the alien home planet.