This episode begins with Æon lying on a stone slab, waking from a dream where she was screaming. We then flash back to earlier where Æon and Trevor are making their individual ways to a Breen research base researching an ancient virus that apparently causes insanity and formed a basic part of early humanity until humans developed an immunity. Æon is cornered by the Breen soldiers near the base but is sucked down and finds that although the base has been there for under a month, it looks like it has been derelict for centuries. There, Æon finds a young boy who guides her through the base and eventually shows her a vial of virus, the only intact vial out of a set of five. There is also a giant fanged baby, apparently the first test subject for the virus, stalking the caves ....