The Fellows reunites the characters of Edwin G Oldenshaw (Richard Vernon) and Ian Dimmock (Michael Aldridge) from the earlier series The Man in Room 17. This series saw the pair relocated to All Saints College, Cambridge University, where they were appointed to the Peel Research Fellowship. Their research was "to investigate the general proposition that, in a period of rapid social change, the nature of crime (and therefore criminals) would change."
Their research lead them into encounters (though never physical) with gangland boss Alec Spindoe (Ray McAnally), who eventually ended up behind bars thanks (unknown to Spindoe) to psychological pressure from Oldenshaw. The Spindoe character was to return in his own series, Spindoe in 1968, which charted his attempts to regain his criminal empire after release from prison.