Bella Manningham thinks she's losing her mind. In the evenings, she hears strange sounds and the gaslights dim for no apparent reason. But is she losing her grip on reason, or is it being loosened for her? Patrick Hamilton's 1938 play gave us the word we now use for an insidious form of mental abuse. This new adaptation from Johnna Wright and Patty Jamieson is a gripping thriller: Will the gaslight have its intended, murderous, effect?