Catherine Chandler comes from a rich family. She works for her father at his law firm. Her life is full of people that are nothing more than acquaintences. She feels as if everything in her life is superficial. While at yet another party she decides to just leave. As she is walking through the park she is mistaken for someone else and is pulled into a van full of thugs. They slash her face and beat her up, then they push her out of the van and leave her for dead. A shadowy figure appears and carries her to secret set of forgotten tunnels below the city. There he bandages her wounds and helps to nourish her back to health. One day when Catherine is feeling better and has regained her some of her strength she begins to take the bandages off of her face. She walks to the wall and finds something to look into and she sees what the thugs have done to her face for the first time. Then she sees finally who her rescuer was. She screams at his apperance and throws what she was looking in at him

A slasher that kills with claws and leaves the victims looking as if they were mauled by a bear is on the prowl. He attacks on the subway. Most of his victims are older. 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. She talks to him about it. In a way this upsets him, but he tells her that it is not him. She is relieved when she finds out for sure that it is not him. Especially since the true culprit is a very unexpected source.

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 hostages 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. When the voodoo priest attempts to sacrifice Catherine, Vincent comes to her rescue, starting a fire when he pushes over the altar table. Mistaking Vincent for his god, the priest walks into the fire and is destroyed.

Vincent alerts Catherine to possible wrong-doing at a well-known, renowned orphanage. Her investigation leads to the discovery of a child-selling scheme operated by the orphanage's owner and a thief who uses the children to steal for him. Catherine rescues a brother and sister (Eric and Ellie) and takes them to live in the tunnel world.

Laura, a deaf-mute tunnel dweller, witnesses the murder of a police officer, for which another man is framed. She goes above with Catherine, but is kidnapped by the real murderers, who are also police officers. Cuffed to a pipe in the basement of the murderer's house, Laura taps out an SOS, which is heard by Pascal and Vincent rescues her. She decides to return Above to live.

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. When her attempts to contact someone fail, she wanders the tunnels, tripping a trapdoor which sends her tumbling down to Mouse's quarters. He leads her to the others. Mouse can save Vincent and Father, but needs demolition supplies. Catherine goes back to Elliott Burch, who gives them to her, no questions asked. Mouse succeeds; Vincent and Father are freed. Father is much more understanding of Vincent and Catherine's relationship. Catherine tells Vincent she loves him and he watches her as she returns to her world.

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. Joes 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-fiance resurfaces. He has all ready been in a mental institute and is very strange. Vincent has dreams of disaster connected to Catherine. He warns her but she thinks that he is paranoid or jealous. When trouble does come to her Vincent is right there.

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

After faking that Catherine hit him young Tony Ramos winds up living with Catherine. She tries to help him by talking to Vincent. Vincent tries to help as well. But it is Tony who winds up trying to reverse unjust banishment of his family before a Gypsy court.

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. This should halt the construction of his tower and also leave the tunnels as a safe place once again.

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