Castiel, Sam, and Dean are all angels that have made the decision to rebel. They are trying to protect the humans from angels and demons alike, and are forced to adapt to the human world, while trying to find Lucifer and fend his minions off.

Kate, a newly turned pure-blood werewolf is just running away from two so-called FBI agents that are trying to kill werewolves and other monsters. She decides to live off of the hearts of monsters instead of humans. She does not want the monsters to put others through the pain that they put her through.