On a walking tour of English cathedrals, Donald Meadows meets Hester Granthem in church. Hearing he is from that hot-bed of crime, Chicago, Hester asks Donald to help her in a robbery she has planned. Thinking it a joke, he plays along; but Hester is serious, and hearing that she plans to rob Mr. Waller, the man who has cheated her father out of thousands of pounds, Donald agrees. A robbery at a pub is arranged, but the Bishop of Broadminster, an avid mystery fan, and his sister stumble into it. Playing detective the Bishop complicates matters and each side, the Bishop, the unscrupulous Waller, the gang Hester hires, and Hester and Donald, each get the upper hand along the way.

Un obispo aficionado a los misterios se ve implicado en uno de verdad.