Violet Morgan is found dead in the library of Winchcombe Hall. She is found where she always used to read after dinner. Mortified, her daughter Gloria Morgan visits Sherlock Holmes. She accuses her father of murdering his wife so he is legally able to marry his mistress Eva Dann and acquire Longparish Estate, but the local doctor Lambeth is insistent her mother died of lockjaw. Holmes and Watson dash to Andover to untangle the disastrous events of the night before last.