Post-apocilipse movie
Starts in a small camp in the mountains. Man about 20 show to take some of the teenagers. He is an immortal that doesn't age
They go to a bunker an begin to party.

Teenage Caveman (TV Movie 2002) - IMDb

Teens encounter people, who, after being used as guinea pigs for the experimental testing of a virus can live forever in a post apocalyptic world.