Terminal

In this sixth and concluding book of the Tunnels series, the
Styx and their cohorts of deadly Armagi have swept across England,
leaving death and devastation in their wake. It seems nothing
can stop them now.

Only a miracle can save the day and, in the inner world at the centre
of the earth, Will and Elliott might just have stumbled upon
one as they uncover ancient secrets that are fundamental to all
human and Styx life.