Catherine Chandler comes from a rich family and works for her father’s law firm. After leaving a party early, she’s mistaken for someone else and is pulled into a van full of thugs. They slash her face and beat her up, then push her out of the van, leaving her for dead. A shadowy figure appears and carries her to secret set of forgotten tunnels below the city.

A subway slasher that kills with claws and leaves the victims looking as if they were mauled by a bear is on the prowl. When Catherine finds out about the case she starts to suspect Vincent, as she remembers how he rescued her from the attackers in the safe house.

Catherine falls for megabucks developer, Elliot Birch. Elderly people are being thrown out of their homes.

Vincent is blinded after an explosion and must escape a street gang that is holding him hostage. Once he is free he must find his way home.

Halloween night Vincent goes above to meet an Irish writer named Brigit O' Donnell. Halloween is the only night that Vincent is safe above. Catherine is at the same party. Eventually, they wind up spending the evening together as Catherine shows Vincent her world.

Catherine has a nearly fatal confrontation with an ex-tunnel dweller, named Mitch Denton.

Vincent is captured and held hostage by two scientists who stick him in a cage. Catherine considers a new job in Providence.

Father's past is revealed when he goes above for the first time in over thirty years to see a friend. When he gets to his friends office he finds his friend is dead. Father is then charged with murder.

An investigation into the mysterious death of a wealthy business man leads Catherine into the world of voodoo. After her apartment is vandalized and she is terrorized, Vincent seeks the aid of Narcissa in an attempt to understand what is happening to Catherine.

Vincent alerts Catherine to possible wrong-doing at a well-known, renowned orphanage.

Laura, a deaf-mute tunnel dweller, witnesses the murder of a police officer, for which another man is framed.

Attempting to aid an injured child (Eric) in the Maze, a cave-in traps Vincent and Father. Catherine, after facing Elliott Burch, who has agreed to be a witness against an extortionist, senses something is wrong and rushes to the tunnels.

"Romeo and Juliet" are in Chinatown. An angry Tong invades the tunnels with his army.

Paracelsus, a former friend of Father's, sells an hallucinatory drug in the world above.

Vincent and Catherine prepare gifts for the celebration of the anniversary of the day they met. Joe is distracted by a beautiful woman named, Erica Salvin.

Vincent's foster brother, who is also Father's son, Devin, returns to the tunnels after a 20 year absence.

Steven Bass, Catherine's ex-fiancé resurfaces, and is behaving oddly.

While exploring a section of the tunnels Mouse discovers a treasure ship. Cullen's greed brings strife.

Paracelsus kidnaps Catherine, which causes Vincent to begin a quest to rescue her.

Construction of the Birch tower is causing many problems in the tunnels. To help the problems stop Catherine agrees to marry Elliot Birch.

Catherine's pain about her fragmented life almost causes her to end her relationship with Vincent.