Soul trade - Thomas E Sniegoski

Some people collect baseball cards, some people collect Beanie Babies... some people collect souls.
A vision of a young girl in pain leads Angel, Doyle and Cordelia to the scene just moments too late - the girl of the vision is being taken unconscious to hospital. The only clue as to what could have happened to her is an ornate glass vial found at the foot of her bed, which Doyle recognises as used for the containment of human souls. It seems souls have many uses (other than the obvious): no two are alike, and the soul of an innocent child is one of the most eagerly sought-after items on the demonic black market. Angel knows the value of a human soul, for his is the source of his own salvation. But can he find this young girl's in time to save her?
Nor is she the only one in danger. For no sooner has Angel made his presence known than the demonic dealers in souls realise that there's another soul out there which is quite literally priceless...a soul more unique than they could ever have dared to dream...