While working late in his home, a man hears noises. The lights flicker and he calls out to see if anyone is there. He is then found dead and the team investigates. They meet with Deputy Fisher who tells them they don't get many murders in their small town. He says the victim is an architect named Alan Foster who was alone in the house. Teresa tells Cho to look for a sign of a break in. Patrick asks Fisher if he killed Alan and he says no. Patrick notices Alan has a brass button in his hand. They see it has the letter B on it. Patrick asks the deputy if it means anything to him and he says no.
The team looks around the house. They see that there was a sign of a struggle and Alan was pushed through the window. Patrick asks Fisher what is troubling him. He admits that he thought the B could stand for Beckworth, the original owner of the house. He says there are rumors that he haunts the place. Cho announces that there are no signs of entry other than by the victim.
Grace talks to Wayne about the benefits of volunteering. Wayne tells Cho that he thinks Grace is dating someone at the homeless shelter she is volunteering at and Cho tells him he needs counseling.
Teresa tells Grace and Wayne that the killer got in without tripping the alarm. Patrick asks Grace if she believes in ghosts and she says yes.
Cho and Teresa meet with Alan's wife Lilian. She says Alan always spent time in a house before making changes to it. She says she was home alone the night of his murder. She says Alan fought with a local hippie named Victoria Abner who was a descendant of Beckworth. She says Victoria thought Alan stole the house from her and sent some intimidating emails.
Patrick tells Teresa that Beckworth was killed while fighting over a woman. He says he was thrown out of a window just like Alan. Patrick asks Alan's wife if Alan told her about hearing noises. She says he told her he heard strange groans at night and things looked like they had been moved.
Teresa sends Cho to talk to Victoria. Patrick tells him to ask her about the ghosts, but Teresa says they don't exist.