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

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.

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'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.

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.

A stress-aggravated illness triggers Vincent's collapse. Vincent goes far back through the catacombs of the tunnels to hide in a cave. While in there he continually growls and thrashes about as if he's gone mad. Catherine goes after him because she says that she can't stand to see him like that. After all he is the love of her life.

Catherine finds out while visiting Joe in the hospital that she is pregnant. As she heads to her car in the parking garage she is kidnapped. Due to Vincent's recent illness he can not sense where she is. He knows nothing of the child that she carries. The kidnappers lock her in a cell. They want only the child. They think that if they take the baby they will get Vincent to emerge and that is exactly what they want. They continue to hold Catherine captive as Vincent frantically searches for her. It seems completely hopeless without his sense of her. Yet he vows to find her no matter the cost.

Vincent takes Catherine from the rooftop back to her apartment. He lays her on her bed. He stays with her until the morning just watching over her. The D.A. finally finds her body. They begin to investigate not only who killed her but also who brought her back to her apartment. Vincent begins the search for his son.

Elliot Birch betrays Vincent ... and dies?

Diana notices things in Catherine's apartment that have Vincent's name on them. She begins to realize that Vincent was her lover and probably the father of her child. She then decides to go to where Catherine is buried and wait for Vincent to do the same. One night it works. Vincent is sick and literally falls on top of Catherine's grave. Diana finds him and carries him back to her apartment where she nurses him back to health.

Vincent breaks free and is barely in time when he burst through the door of the nursery where Gabriel is getting ready to suffocate the baby. Vincent attacks him and would probably have killed him if Diana had not burst in and told him to stop. To keep Gabriel away from Vincent and the baby Diana is forced to shoot him. Vincent then takes the baby and goes below. He names the child Jacob after Father. During the naming ceremony Catherine is shown behind Vincent as if she is his gaurdian angel.

Rolley is shot while trying to rob a liquor store. He then returns below. Vincent destroys Gabriel's drug house. Vincent entrusts Snow's ring to Diana.

Dimitri, a Russian sailor unknowingly brings the plague below.

Michael leaves to the tunnels to go to college above. Vincent deals with jealousy issues of not being able to go to college above. Catherine befriends him and helps him settle in. Michael eventually falls for Catherine and winds up kissing her. Then he is afraid of what Vincent will do when he finds out about the kiss.

Catherine's father dies and Vincent allows her to come below to grieve. He also makes her go back above because he knows that she does not belong there no matter how he feels. Catherine finally agrees and goes back above.

Catherine is harrassed by a peeping tom. The worst part is that this man has seen Vincent!