The play is set in fog-bound London in 1880 at the lower middle class home of Jack
Manningham and his wife Bella. It is late afternoon, a time which Hamilton notes
as being the time "before the feeble dawn of gaslight and tea".
At the opening of the drama Bella is clearly on edge, and the stern reproaches from
her overbearing husband (who flirts with the servants) makes matters worse. What
most perturbs Bella is Manningham's unexplained disappearances from the house: he
will not tell her where he is going, and this increases her anxiety. As the drama
unfolds, it becomes clear that Manningham is intent on convincing Bella that she
is going mad, even to the point of assuring her she is 'imagining' the gas light
in the house is dipping.
The appearance of a police detective called Rough soon leads Bella to realise that
far from going mad, she is married to a psychopath. Rough explains that the apartment
above was once occupied by one Alice Barlow, a wealthy woman who was murdered for
her jewels but that the murderer never uncovered them.
It transpires that Manningham goes to the flat each night, searching for the jewels
and causing the light in the house below to go down. Rough convinces Bella to assist
him in exposing Manningham as the murderer, which she does, but not before she takes
revenge on Manningham by pretending to help him escape. At the last minute she reminds
him that, having gone 'mad', she is not accountable for her actions. The play closes
with Manningham being led away by the police.
The storyline may sound familiar to you as the play has twice been made into a film,
in 1940 and 1944, and it remains one of the longest-running non-musicals in Broadway