In San Francisco, Sam and Dean investigate a series of murders of a werewolf where the victims have their hearts removed. When a lawyer is killed in his office, the Winchester brothers visit his assistant Madison and they believe her former boyfriend Curt is the killer. Sam stays in Madison's apartment to protect her and they fall in love for each other while Dean investigates Curt; however, they discover that Madison is actually the monster and they give their best efforts trying to save her from her fate.
—Claudio Carvalho, Rio de Janeiro, Brazil