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

CASTAnna Diaz - Saran MorganGed Diaz - Sion Daniel YoungRuth - Michelle BonnardRaymond - Ioan Hefin Nell - Diana Yekinni Maggie - Catrin Aaron

Original music by Sion Orgon and Rhodri Davies

Production Coordinator Lindsay ReesSound Design by Catherine RobinsonDirected by Fay LomasA BBC Audio Wales production for Radio 4