The Three Dog Detective Agency of Chula Vista has traveled far and wide in their fight against evil. This time, however, they go where no dogs have ever gone before, through space and time and into alternate timelines. To battle the evil of Lord Cerberus, a foe unlike any other, they must ally themselves with the intrepid Dogs of S.T.E.A.M. Together, they fight not for the fate of one world, but several.

When schoolgirl Lisa Martin vanishes from the Hammershire village of Midriven, newcomers claim she ran off with a boy or was abducted by an escapee from Irongate Prison, but old timers know better. She was taken by the Beast, a nameless monster, though some call it a god, that has roamed primeval Robbers Wood since before the advent of man. When DCI Arthur Ravyn and DS Leo Stark of the Hammershire Constabulary are called in, the elder villagers shake their heads. The Old Gods keep what they take. Even if they do find the girl's savaged body, they will surely die themselves. What chance do two...