Dr. Kelson finds himself in a shocking new relationship - with consequences that could change the world as they know it - and Spike's encounter with Jimmy Crystal becomes a nightmare he can't escape.
| Actor | Role |
|---|---|
 Ralph FiennesDr. Kelson | Dr. Kelson |
 Alfie WilliamsSpike | Spike |
 Jack O'ConnellSir Jimmy Crystal | Sir Jimmy Crystal |
 Erin KellymanJimmy Ink | Jimmy Ink |
 Chi Lewis-ParrySamson | Samson |
 Connor NewallJimmy Shite | Jimmy Shite |
 Maura BirdJimmy Jones | Jimmy Jones |
 Ghazi Al RuffaiJimmy Snake | Jimmy Snake |
 Robert RhodesJimmy Jimmy | Jimmy Jimmy |
 Emma LairdJimmima | Jimmima |
 Sam LockeJimmy Fox | Jimmy Fox |
 Gareth LockeHunter | Hunter |
 Celi CrosslandPregnant Infected | Pregnant Infected |
 Mirren MackCathy | Cathy |
 Gordon AlexanderJonno | Jonno |
 Louis Ashbourne SerkisTom | Tom |
 David SterneGeorge | George |
 Elliot BennMatthew | Matthew |
 Lynne Anne RodgersJane Ji | Jane Ji |
| SSebastian Williams-BarrowSamson (Child) | Samson (Child) |
 Natalie CousteauTicket Inspector | Ticket Inspector |
 Maiya EastmondSam | Sam |
 Cillian MurphyJim (uncredited) | Jim (uncredited) |