Showing Down the Garden Path by Dorothy Cannell

Tessa Fields was left on the doorstep of an English vicarage and adopted by the vicar and his wife. At 21 she’s devised a plan to discover who her birth mother was. Her plan involves suitor Harry Harkness, and faking amnesia, and imposing on two elderly ladies. Amidst a cast of eccentric characters, Tessa is not entirely surprised by the bizarre murder she stumbles on. Mystery by Dorothy Cannell; originally published by St. Martin’s Press