This clever “who done it” is by Ken Ludwig, the author of Moon Over Buffalo and Lend Me a Tenor. Taking place in 1922, actor, manager and playwright William Gillette (of the local Gillette’s Castle in Connecticut), has invited his sister and the cast of his latest revival of “Sherlock Holmes” for a weekend of relaxation at his magnificent medieval castle on a bluff overlooking the Connecticut River. For entertainment Gillette has arranged a séance. Now the scene is set for his greatest role. Someone is trying to murder him and he suspects it is one of his guests. The intrepid, eccentric Gillette plans to solve the case himself a la Sherlock Holmes.