Test pilot Tuck Pendleton volunteers to test a special vessel for a miniaturization experiment. Accidentally injected into a neurotic hypochondriac, Jack Putter, Tuck must convince Jack to find his ex-girlfriend, Lydia Maxwell, to help him extract Tuck and his ship and re-enlarge them before his oxygen runs out.

The US military is running a test for a special type of radio transmitter, to be used to communicate with submarines, in a deep system of underground caves in Central America. When the signal from one of the transmitters suddenly disappears, a team of soldiers led by Major Elbert Stevens and cave specialists led by Rupert 'Wolf' Wolfsen including scientist Leslie Peterson are sent in to find out what happened. Exploring deep underground, they stumble upon a tribe of albino cave-dwellers who have apparently been isolated from the rest of the world for thousands of years. The cave-dwellers are hurt by radio frequencies and are able to see in infra-red frequencies, tracking the explorers by their body heat.

In the late 1960s, three Harvard students Jessica, Leo and Nick grow close as they undergo personal changes, but their friendship is jeopardized by romantic feelings both men develop for Jessica.

After her younger sister gets involved in drugs and is severely injured by contaminated heroin, a nurse sets out on a mission of vengeance and vigilante justice, killing drug dealers, pimps, and mobsters who cross her path.