Grendel: Devil's Crucible - Defiance (Grendel: Devil's Crucible - Defiance #4)

After surviving the Anti-Grendels and a double vampire attack, Grendel Prime, Ptolemy, and Hari Smythe finally make it to the Grendel Grotto, the base of the Hounds of Orion. With Grendel Prime's help, they may be able to finalize a special experiment that's taken years to develop - an experiment that could change everything!