The year is 1917. Following the sudden death of his Professor, a young man and his two companions are approached by a strange man who gives them a book to safeguard. This book, the Imaginarium Geographica, is the reason the Professor was killed, and now, they too are in mortal danger.

Chased by the ferocious Wendigo, half-man half-werewolf creatures, the three companions seek refuge on a ship - a ship that leads them to the extraordinary lands of myth and legend mapped in the precious book they carry. As their adventure unfolds we learn that the friends are in fact C.S Lewis, J.R.R Tolkien and Charles Williams - and as they discover that events in the known world mirror those in the imaginary realm, they come to realise the importance of the Imaginarium Geographica , and if not protected, there will be no peace from the war that rages in our world.