Set in St. Petersburg, Florida, Cocoon tells the story of a group of elderly folk who get a new lease of life when they stumble across an alien "fountain of youth" in a disused holiday home. Unbeknownst to them, aliens have been using the swimming pool in the house to store their cocooned brethren, giving the waters a powerful, rejuvenating quality. Energized with youthful vigour and vitality, they must choose between accepting their impending deaths or having eternal life.