The storm rages outside, and soon no one can come into or out of Bly.

As things in the surgery become increasingly chaotic, Anna, Ged and microbiologist Nell start to get closer to understanding what might be causing the illness - but still no closer to treating it. And with the pathogen now spreading at breakneck pace, Ged finds himself struggling to cope.

Dark Medical Thriller by Matthew Broughton, creator of Tracks and Broken Colours.

With original music by Sion Orgon and Rhodri Davies

CAST Anna Diaz - Saran Morgan Ged Diaz - Sion Daniel Young Ruth - Michelle Bonnard Raymond - Ioan Hefin Nell - Diana Yekinni Maggie - Catrin Aaron

Original music by Sion Orgon and Rhodri Davies

Production Coordinator Lindsay Rees Sound Design by Catherine Robinson Directed by Fay Lomas A BBC Audio Wales production for Radio 4