Mrs McCarthy might have found a suitor in Patrick O'Leary. She has been helping out with his garden since his gardener ran off somewhere.
O'Leary is a retired bible salesman who suffers from ill health. He is a god fearing man.
When a drunken woman barges in threatening to expose him. Mrs McCarthy is shocked to find out that she was his gardener. Worse he is also married to her. She then dies, reputedly poisoned.
Inspector Mallory arrests a local who drank with the dead woman a lot. Father Brown believes the O'Leary household hides more secrets. Mrs McCarthy is heartbroken.
Another enjoyable mystery, the focus is more on Mrs McCarthy in this one. As ever Father Brown has been beavering away in the sidelines and arrived to his own solution.