First broadcast 12th/13th February 2024.
The Lyell are called to a museum outside King's Cross Station, where they discover the bodies of eight victims entombed below.
Emilia Fox - Dr. Nikki Alexander
David Caves - Jack Hodgson
Aki Omoshaybi - Professor Gabriel Folukoya
Alastair Michael - Velvy Schur
Rhiannon Jones - Cara Connelly (as Rhiannon May)
Hermione Norris - CS Sheila Court
Michèle Winstanley - Barbara Apstead
Mark Oosterveen - Newscaster
Monika Miles - Anna Górska
Colin Stinton - Ted Holmes (voice)
Rupert Holliday-Evans - Russell Drake (as Rupert Holliday Evans)
Sharon Rose - DC Chloe Abbott
Steve Nicolson - Keith Pryor
George Watkins - Carl Streeting
Ellen Thomas - Esther Daniels
Hayley Carmichael - Joanne Perry
Jude Akuwudike - Malcolm Jones
Lisa Allen - Tourist
Neil Pearson - DI Steve Tudor
Ty Hurley - Fire Fighter
Neil Hobbs - Mike Jarvis
Melanie Kilburn - DI Mel Granger
Sally Rogers - Mary Streeting
Anne Lacey - Gillian Kerr
