Cocoon is a warm-hearted science-fiction fable that avoids becoming overly corny thanks to the performances of its mostly senior cast. Wilford Brimley, Don Ameche, and Hume Cronyn are three old-timers who sneak out of their retirement home a few days a week to swim in the large pool on an abandoned estate next door.
When the threesome begins to feel curiously younger, they discover strange pods on the floor of the pool. These pods are alien cocoons, which are being pulled from the ocean by a team of extra-terrestrials in human form led by Walter (Brian Dennehy), who has hired a local charter operator (Steve Guttenberg) to assist him.
Walter explains to the seniors that energy from the cocoons is restoring youth and vigor to the older men every time they go for a dip. The aliens agree to let the men continue to swim in secret, but of course they can't keep their discovery to themselves.
Soon the pool is swarming with retirees, with the notable exception of Bernie (Jack Gilford), who has no interest in prolonging life any longer than necessary. The aliens ultimately prepare to return home and offer the retirees eternal life if they leave Earth behind as well.
Director Ron Howard treats his old-timers with care and dignity, and they respond with deeply sympathetic performances (Ameche won the Best Supporting Actor Oscar); the film's science-fiction trappings ably sustain the story's all-too-human ruminations on youth, aging, life, and death.