Joe Finley, Ben Luckett and Art Selwyn are three pensioners who pass time in their retirement home. Each time they can, they go in a close unoccupied house to use it's sumptuous pool. Jack Bonner survives as he can by proposing tourist ballads on board his boat. When a couple proposes him to rent his services for a period of 27 days, it is for him a real windfall.
The peach exerted by his benefactors is not nevertheless of ordinary nature, however Jack doesn't ask questions when the former recuperate strange cocoons and place them on the bottom of the pool where the old men go. The commotion exerted by these manipulations wakes up their curiosity but they do not modify their aquatic habits.
For them, things are going to change radically. These three kindy old men see their physiognomy changing. Multiplying their swims in the pool that shelters increasingly cocoons, they find an insolent health, making them forget their litle physical harassments finding even back a certain sexual appetite. About Jack, he makes a discovery of another nature. He understands that the people who rented his boat and the house are not from this world. Walter Firmin, who seems to be their chief and the beautyfull Kitty explain him that they are Antharians from planet Anthares and that they have come to seek these abandoned cocoons laid there 10.000 years ago.
What had to happen arrives, our three accomplices are caught. But thanks to Ben's insistence who explains that the pool seems necessary for the recovery of the Joe's cancer, Walter unveils them their real nature and authorizes them to use it if they do not touch the cocoons, thoses that provide water the vital energy source.
Except for Bernie and his wife Rose, all profit of the pool and find a second youth. But things finish to be known and the jealousy of the other boarders of the retirement home provokes an assembly in the pool that loses little by little its vital forces. Firmin is angry. Cocoons that shelter the beings of their species no longer have enough energy to survive before the quasi imminent arrival of the spaceship that has to return them back home...
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Feeling guilty for the pain that they provoked, Ben proposes Walter to put cocoons back in the ocean before returning to Anthares in the meantime that another mission comes to seek them. All give a hand to help the aliens. Walter makes them a proposal : he invites thirty of them to embark on the spaceship and to discover a new life in which they will become immortal.
Ben and Mary accept leaving despite them their grandson David who understands their choice. Time for departure has arrived. Except Bernie who lost Rose, his wife, boarders of the retirement home embark on Jack's boat. But the alert is given and the police throws in search of this large handle of senior runaways. Nevertheless nothing will be able to prevent the flying saucer to come and get them. Except Jack who despite Kitty's departure he is in love with, stays on Earth, a new life begins for our eldery people.