Logan’s Run is a 1976 American science fiction action film directed by Michael Anderson and starring Michael York, Jenny Agutter, Richard Jordan, Roscoe Lee Browne, Farrah Fawcett, and Peter Ustinov.
It depicts a future society, on the surface a utopia, but soon revealed as a dystopia in which the population and the consumption of resources are maintained in equilibrium by killing everyone who reaches the age of 30.
Ha! He doesn’t know what to do with the three seashells!
No wait, wrong movie