Sid thinks he has struck it lucky after he wakes up with a hangover and a beauty next to him in bed and she is an heiress to a brewery.
However the brewery has burned down, her father is killed and Grace Fitzgerald is the main suspect. Sid gets Father Brown to investigate and there are other suspects such as a disgruntled employee who might had committed the arson.
Poor Sid, just as his thought his luck was in, it gets cruelly snatched away, not helped that Grace is married. However the evidence against her does not look too good.
A somewhat simple but contrived mystery as you always think that Sid might had been used rather conveniently here and Father Brown thinks the same. At one point you are left wondering if the culprit has got away with it.