Gravel: Combat Magician #3

On a clandestine mission to Tokyo to clean up the mess created by another British Combat Magician, Gravel must find the rogue madman or risk an international incident. But once he comes face-to-face with his occult-powered foe, the seasoned veteran will find that the green trainee has brought something with him from England, something which makes him impervious to harm. In the underground subway of magical horrors, Gravel's only hope is to use his head, which has never been one of his strong point, and even if he survives, a far greater threat to his life awaits in the darkness!