
District attorney Catherine Chandler, after being attacked and left for dead, is rescued by a half-man/half-beast named Vincent who lives in secret caves and tunnels beneath New York City. When Catherine returns to the surface to resume her life, she and Vincent are not only in love, but share a powerful psychic bond that enables Vincent to sense whenever Catherine is in danger. The plotlines revolve around Catherine getting in danger and the dashing and powerful Vincent coming to her rescue.

Diana is seized by Gabriel's henchmen and forced to summon Vincent to the aid of his gravely ill son.

Father's visit convinces Joe to organize a citywide search for the house where Gabriel is holding Vincent captive.

Diana stalks a serial killer of ex-tunnel dwellers; Father reunites with a former love (Fionnula Flanagan).

Diana learns that the series of murders she's investigating is linked to a tragedy that occurred in the Tunnel World more than 20 years ago.