Colliery manager Richard Sharpe (Mark Williams - Father Brown) is desperate to get hold of a mysterious diary left behind by Prem's predecessor Dr. Elwyn, and hires local street urchin Dan Griffiths to steal the book from the surgery. However, he underestimates Kamini's attentiveness, and the lad is caught in the act, leading to a heated confrontation. Meanwhile, the doctor has an emergency of his own to deal with when he is asked to make an unusual house call.