Lady Felicia's driving lands her and Mrs McCarthy in the cottage hospital, where elderly Mrs Garrity dies during a routine operation carried out by Sir Malcolm Braithwaite and womanizing Dr Tony Fairfax. A nurse who voiced her suspicions of foul play is murdered and the inept Inspector Mallory believes she was killed by Fairfax, who once worked with her. Father Brown however links a seemingly random comment made by Mrs Garrity to a secret one of the staff is keeping but he must act fast as Mrs McCarthy's sleuthing has put her in danger.
Quite an enjoyable episode with Felicity and Mrs McCarthy ending up in hospital where there's a murder - a nurse ends up in a cupboard with a scalpel in her stomach after airing her view that a patient's death on the operation table was murder - and some fun from my favourite character, Inspector Mallory, who is so over the top, uncouth and thoroughly useless as a detective. He's a spoof of the inept detective like Sherlock's inspector Lestrade.