The sleepy Welsh mining village of Trefelin is in for a shock. When the local doctor dies, his replacement isn't quite what people expect - Prem Sharma is the Indian doctor.

Colliery manager Richard Sharpe is still desperate to find a mysterious green leather diary left behind by Prem's predecessor, Dr Elwyn.

The Indian Doctor's wife, Kamini Sharma, is still desperate to leave the village of Trefelin. But as she tries to escape, she finds herself becoming the only person who can help local tearaway Dan when he gets into trouble.

The village of Trefelin is preparing for the annual summer fete, but there's a lot going on behind the scenes. Dr Sharma is preparing to leave the village for good, and Mrs Sharma goes in search of the missing Dan - but she finds more than she bargained for.

Sharpe has been promoted, and Megan pleads with Dr Sharma to stay and help the miners fight for justice. The series builds to a climax as the doctor takes on Sharpe once and for all...