When a third Helper is killed, Vincent and Diana find a common thread and believe this is the end.
Diana takes the ring to a jeweler to find out information on it, but through it she is connected to Vincent. Gabriel tells her that Vincent's son is dying and without his father the baby will die.
Diana takes Vincent to her home, and cares for him as best as she can. For three days he hovers between unconsciousness and delirium.
The man who killed Catherine and took her baby sends an assassin to get Vincent. He manages to find the underground world and goes looking for him. Vincent upon learning of his presence tries to lead him away from the others.
Vincent carries Catherine back to her apartment. He stays with her until his enemy, the dawn, forces him to leave.
Catherine walks fearlessly into the dark cave, where Vincent is roaring in rage and fear, apparently in control of the 'Other' side of himself.
Vincent and Cat find themselves at odds on how to deal with Agent Reynolds, which forces Vincent to wonder if he is more beast than man.
After getting stonewalled by Cat in his quest to track down a suspected beast, Gabe enlists Vincent’s help, but Vincent quickly takes matters into his own hands.
Vincent's decline accelerates, and everyone in the tunnels fears for his sanity. Only Catherine can calm him.
Though the lies of an evil man, the campaign to destroy Vincent's humanity continues, until he is forced to kill an unharmed innocent man.
Someone who knows a great deal about Vincent and Catherine gives a reporter information and their lives are thrown in turmoil.
Vincent witnesses the murder of a young woman in the park. When Catherine fails to convict them, Vincent begins to watch their every move to stop them from killing again.
Elliott Burch returns and exposes Catherine to danger and Vincent is again haunted by the life Catherine could have with someone else.
These include the somewhat Vincent-less "Trial," in which Catherine prosecutes a man accused of killing his son.
Catherine must got o LA to investigate a murder.This is the first time her and Vincent had been so far apart and they are both concerned.
On the second anniversary of their firt meeting, Catherine and Vincent's idyllic peace is shattered by an obessed intruder, who threatens not only their secret but Catherines life.