Miss King's uncle Charles has been staying at the Elizabethan hotel but his return is overdue so she goes to collect him . However she finds the hotel staff have devised ways to stop them and other guests from leaving in a plot to rob and kill them or in Charles' case for his business to be taken over in his absence. Miss King leads a successful revolt of the prisoners just in time for Steed's arrival.
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Did You Know?
The Edgewarebury Hotel ("The Elizabethan" in this episode) also appeared in feature films "The Rough And The Smooth" (1959) and "School for Scoundrels" (1960), where it doubled as the tennis club where Palfrey takes on Delauney; also in Randall & Hopkirk (Deceased) episode The House On Haunted Hill [16/11/69] See more
It's a simple case. A man with the mentality of a child of seven could handle it.
On that basis, Basil qualifies.