Father Chadwick Vita was a monk who presided over the church of a small English village. One day he came across a mysterious entity with healing powers whom he thought was an angel. He took the 'angel' to his church and cared for it, developing a quasi-paternal attitude towards it.
As the entity's powers became known, Father Vita would take the ill to the 'angel' to be healed. When it sensed that its enemy had come close to finding it, he comforted it and reasssured him that nobody was after him. He urged it to soldier on and fulfil its God-given mission to help others.
During an apparent outbreak of the Black Death, Chadwick encountered the Tenth Doctor, who sought the faith healer he had heard about. The Doctor left after being shown the 'angel' doing its work with the sick. He however soon returned chased by three Macro-viruses, which Father Vita mistakes for demons. Realising these 'demons' are the enemies he was warned about, he tried to get to the 'angel' before they do, but was attacked. As soon as the healer regained his full powers he was the first one to be saved and healed. Father Vita asked the healer to stay, but it left to win its war against the viruses on its home planet.