The scene opens in O’ahu on Halloween. Two teenagers are walking around trying to find the “Night Marchers”. They go to Sacred Ground where the girl finds a backpack in the dirt. She screams and they are killed by someone. Meanwhile, Danny takes Grace around the Hotel to “trick-or-treat”. They come up to one door and they guy says that he doesn’t have anything. Danny says that he is sure that he can find something. The man comes back with mini-alcoholic drinks. Danny shows his badge, but is interrupted from a phone call. He says that he is lucky. Danny tells Grace that he has to take her back to Rachel’s. Grace doesn’t seem sad about it at all. He gets on the scene and a homeless man tells Danny to get away. Danny ignores him and tells him to go away. Kono tells that the victims were two documentarians who were trying to film the “Night Marchers”, Hawaiian Ghost Warriors. Danny thinks that it is a joke. Kono says that the roommate is the one who found the body sticking out. Danny asks where Lori is and Kono says that she had to change. Lori comes up and Danny and Steve laugh about the fact that she dresses up for Halloween.
They get to the crime scene and Chin Ho tells them that they are waiting for the evidence. Danny sees a hand sticking out of the ground and suggests that they start there. Chin Ho says that they have to wait for the Priest to come and bless them so that they can enter the Sacred Grounds. Danny says that it is a joke and jumps into the Sacred Grounds. He finds the camera that the documentarians were using and asks when the evil spirits are going to do something. When they get back to Danny’s car, they find a rock through the windshield. He tells Steve to be quiet. The next day, Danny tries to find an apartment that he can afford with no luck. He tells Steve that he wants to be able to have Grace stay with him at a nice place. Steve tells Danny that he is going to have to learn to be more respectful for the Hawaiian religious culture if they are going to be able to have HPD’s help with the cases. Danny agrees that he will fake like he is interested. They get to Headquarters and find out that they found there was a white duffel bag in the recording, but not at the scene. They suggest that there were grave robbers and Steve and Danny go visit Max.
When they get there, Max is in a Matrix costume and says that he was taken directly from a costume party. He says that the body had a full fingerprint on the girl’s face and he matched it to Greg Straithan, a man who is dead. They get back to Headquarters and Kono pulls up that Greg died last week. He was shot and killed by his girlfriend, Nikki Royce. Lori says that the mental hospital has her. Steve says that he and Lori will visit her and says that they need to ask the roommate if she has seen Greg. However, she doesn’t. Kono asks how the girl is taking it and she says that she has never been alone. She says that there was a weird guy at the Sacred Grounds and says that he hit his head. They get to the Sacred Grounds and the priest is there. Chin Ho finds blood at the crime scene that they didn’t see before. At the mental hospital, Steve asks Lori about the Halloween party and she ignores him. They get into Nikki’s room and ask about Greg. She says that she shot him, but Steve says that they know that she didn’t. She goes up to Steve and says that Greg haunts her and says that he has to tell the others that she is not crazy. However, it is clear that she is. Lori says that she is crazy and tells her to go with Danny to Greg’s apartment.
Danny arrives and is talking to another apartment complex. A woman with a dog says that there is apartment available if he is looking. He meets Lori inside and she says that there are all signs that Greg was there and shot. The landlady comes in and Danny asks details of the apartment. He takes her to the side and says that, by law, she has to disclose that there was a murder that happened and would have to reduce the rent in half. Lori says that they have the warrant to dig up Greg’s grave. Danny and Steve arrive there and they open up the grave. The funeral director says that he doesn’t like this. However, when they open it, there is no body. Max comes into Headquarters and says that the blood that they found on Sacred Ground wasn’t anyone’s in the system. Kono finds out that the hand of Greg was in the bag on the Sacred Ground. She says that the killer was hiding something.
Gabby is there at the crime scene when Steve and Danny come up. Steve says that Danny is a real believer of everything and Danny pretends to be interested in it. Lori says that they are using software to search for any bodies so that they don’t have to dig up all around. Chin Ho tells Danny that someone threw a rock through his window. Danny says that he already knew about it. However, he says that it is the other one. Danny says that it doesn’t make sense and Steve suggests that the homeless man was the one who did this to Danny’s car. Danny and Steve go out into the forest and stumble upon a campsite where they find blood. Back on Sacred Ground, Lori and Gabby find out that there are several bodies in the ground. Suddenly the man comes out with a machete in his hand. The man tells that Danny doesn’t belong and says that he angered the spirits. They take him to headquarters and Steve says that the man is Samuel Lee, a combat veteran from Vietnam. He tells them that he protects the Sacred Ground and says that he didn’t kill anyone.
Danny tells Steve and Lori that Samuel fits the profile, but it the rest of them say that it is not true. Max says that there are three of the bodies. None of them were married, but says that each had a body part missing. Ligaments were missing and there was liquid nitrogen, a way of preserving body parts. They are not looking for a serial killer, but a businessman who is selling body parts to the black market. Lori says that the funeral director, Tyler Mitchell, is the one who is to blame. They get to the funeral home and split up. Lori goes downstairs and finds that Tyler Mitchell has been embalmed and is dead. Suddenly someone sneaks up on Lori and hits her in the head. Steve gets to her and she apologizes. She says that she is fine and Chin Ho says that the killer is gone. Chin Ho says that the killer was trying to get rid of forms and shows that the person who facilitated with Tyler was Jacob Garrison. They find out that he owns a piece of property outside of the area.
They arrive and Steve says that a very flammable substance is on the floor. They hear shouts from Chin Ho and Lori. They find Jacob and he has a lighter. They tell him not to do it, but his mind is made up. He drops the lighter and sets himself on fire. The Five-O Team gets out just in time. The next day, the Five-O Team helps Danny move into his new place and he says that he is going to get new things. They get all the things moved in and the landlady comes in with the final paperwork. Danny asks about the pet deposit and she tells him that they have a no pet policy. Danny says that the lady with the dog that told him about the apartment has one. She says that the lady he is describing died 5 years ago. Danny tells the Five-O Team to pack it up and for them to get out of there. The episode ends.