Thomas performs a post-mortem on a soldier who died in military training. His investigation takes a turn when he discovers traces of a possible nerve agent.
| Name | Type | Role | |
|---|---|---|---|
| Michael Crompton | Writer | ||
| Graham Turner | Guest Star | Arthur Simpson | |
| Will Stevens | Guest Star | Private John Sealy | |
| Robert East | Guest Star | Henry Young | |
| Tina Chiang | Guest Star | Simone Taylor | |
| Daniel Stewart | Guest Star | Sergeant Haring | |
| Ash Tandon | Guest Star | DI Karl Guyatt | |
| Elizabeth Boag | Guest Star | Paramedic | |
| William Ash | Guest Star | Major Mark Sealy | |
| Dan Parr | Guest Star | Edmund 'Fish' Fishbourne | |
| Clare Higgins | Guest Star | Professor Katherine Dukes | |
| Adelle Leonce | Guest Star | DS Lucy Vail | |
| Ben Bailey Smith | Guest Star | Lt Col Ben Carmichael | |
| Dominic Leclerc | Director |