The Reverend Justin Somerton, a scholar of medieval history, and his protégé Lord Peter Dattering are visiting an abbey library. While studying a stained glass window, they uncover clues leading to a treasure hidden by a disgraced abbot.
| Actor | Role |
|---|---|
 Michael BryantThe Rev. Justin Somerton | The Rev. Justin Somerton |
| SSheila DunnMrs. Tyson | Mrs. Tyson |
 Anne BlakeLocal Lady | Local Lady |
 Frank MillsMr. Tyson / Father Dominic | Mr. Tyson / Father Dominic |
| VVirginia BalfourLady Dattering | Lady Dattering |
| PPaul LaversPeter, Lord Dattering | Peter, Lord Dattering |
| JJohn HerringtonAbbot Thomas | Abbot Thomas |
| PPeggy AitchisonLandlady | Landlady |