Hellboy makes his way to their large home ... and he encounters a flaming demon - a fire wolf - which he successfully fights off.
Hellboy and Franca make their way to Pompeii, where Franca remembers seeing an image of the fire wolf whilst on an archaeological dig. Hellboy unearths the shriveled corpse of a demon hunter who was buried during the AD 79 eruption of Vesuvius, and it tells him of the fire demon that escaped the grip of the volcano . . . leading to that devastating eruption.
As the volcano rumbles again with a new thirst for human blood an eruption even more devastating than that historical catastrophe looks very, very close.