Events continue to spiral at the university, and Cara becomes collateral damage. The riddle of the body in the Thames is solved. A breakthrough in the Cherry case is received from an unlikely source, but will the team get there before it is too late?
| Name | Type | Role | |
|---|---|---|---|
| Timothy Prager | Writer | ||
| Richard Keep | Guest Star | Harrison Cairney | |
| Kevin McNally | Guest Star | Professor Peter Cherry | |
| John Thomson | Guest Star | DI Warren Bull | |
| Maeve Courtier-Lilley | Guest Star | Vanessa | |
| Emily Piggford | Guest Star | Professor Elizabeth Newport | |
| Ashley Margolis | Guest Star | Haidar Alam | |
| Kaye Wragg | Guest Star | Valerie Fullerton | |
| Isobel Wood | Guest Star | Celeste Locke | |
| Diveen Henry | Guest Star | Elaine | |
| Tracey Rooney | Director |