Four teenagers at a British private school secretly uncover and explore the depths of a sealed underground hole created decades ago as a possible bomb shelter.

Thora Birchas Liz Dunn
Desmond Harringtonas Mike Steel
Keira Knightleyas Frances 'Frankie' Almond Smith
Laurence Foxas Geoff Bingham
Embeth Davidtzas Dr. Philippa Horwood
Steven Waddingtonas DCS Tom Howard
Emma Griffiths Malinas Daisy
Kelly Hunteras DI Chapman
Daniel Brocklebankas Martyn Taylor
Jemma Powellas Minnie (as Gemma Powell)