The team of bells at St. Ethelred church is the pride and glory of the idyllic Cotswolds village of Thirk Magna, together with the most dedicated bell ringers in the whole of England: the twins Mavis and Millicent Dupin.
As the village gets ready for the Bishop's visit, the twins get overly-excited at the prospect of ringing the special peal of bells created for the occasion and start bullying the other bell ringers, forcing them to rehearse and rehearse . . . so much so that Joseph Kennell, a retired lawyer, yells at the sisters that he 'felt like killing them'!
When the twins' home is broken into one night and Millicent is found dead, struck from a hammer blow, suspicion falls onto the lawyer. Will Agatha unmask the real killer and clear Joseph's name?