Horizon explores the findings of physicists at Brookhaven, Long Island, New York. Who, after two years and thousands of photographs, have identified a predicted new particle which has a unique characteristic: 'strangeness minus three'.

Richard Feymann was one of the most brilliant theoretical physicists and original thinkers or the 20th century. He rebuilt the theory of quantum electrodynamics, and it was for this work that he won the Nobel Prize in 1965. In this documentary he talks about his motivations to be a scientist and a teacher of science.