When Hellboy, Liz Sherman and Roger the Homunculus are detailed to investigate an abandoned German castle, they have no idea of the horrors in wait for them - but for once, with a 'failsafe' bomb planted in Roger's chest, and a mysterious, perhaps treacherous guide, it seems that the horrors of real life outweigh whatever they might find...That is, until dead Nazis, a flying brain in a jar, and Rasputin and Baba Yaga are thrown into the melee! Help is coming, from a most unexpected source; but will even the legendary Lobster Johnson be able to help Hellboy, Roger and Liz defeat an evil that predates the very world itself - the all-consuming Conqueror Worm?