The Avengers.S06E33.Bizarre (Series Finale)

When a man who was buried a year previously is found newly dead, Steed investigates the cemetery where the dead man was supposed to be. One exhumation leads to another, as more and more discrepancies are uncovered. Steed then has himself buried alive — to see what transpires.
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Teleplay by Brian Clemens
Directed by Leslie Norman
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Guest Starring: Roy Kinnear, Fulton Mackay, George Innes, John Sharp, Sheila Burrell, Michael Balfour, Patrick Connor, Ron Pember