Plot hole: In the third story, "A Lover's Vow", Carola tells Preston that she was able to get his artwork exhibited at a very prestigious art gallery. At the end of the story, it's revealed that Carola is the very gargoyle that killed Preston's friend and swore him to silence. A very big mystery how a gargoyle, posing as a human, would have any connections to an art gallery at all.
Continuity mistake: In "Lover's Vow", as Preston evaluates the deep, nasty scars he has on his chest from his encounter with the gargoyle, he turns away from the mirror for Carola to tend the wounds. But, when Carola starts treating the wounds, the deep wounds are now shallow streaks of blood rather than deep scars.