Sherlock Holmes - Cry of the Innocents

A mysterious Catholic priest arrives at 221B Baker Street, only to utter the words 'if corpe' before dropping dead. Though the man's death is attributed to cholera, when news of a similar case reaches Holmes, he is convinced that the priests have been poisoned. He and Watson learn that the men were on a mission from the Vatican to investigate a miracle; but surely no miracle could lead to murder?