"Lucas Buck, sheriff of Trinity."
Lucas: "What in the world makes you think I'm looking for that old cousin
Billy: "I feel kinda like the only normal guy in the nut house, present
company excepted, of course."
A mysterious plague has come to Trinity. People suddenly begin bleeding from their eyes and ears. Other people, like E. A. Tippett, see blood everywhere they look. E. A. thinks he is losing his mind so he goes to Sheriff Lucas Buck for help. When he says he will do anything to make it stop, Lucas asks him to set his brother up. E. A. tells Lucas he can't do that to his own brother.
At the hospital, the townspeople and the media are asking Lucas about the outbreak. One man calls him a liar when he says there is nothing to worry about. Deputy Ben Healy and Dr. Matt Crower drive up, followed by an ambulance. Lucas asks Dr. Matt to help him out and Dr. Matt tries to calm them down. When a man asks if they have another bleeder, Dr. Matt lies and tells him it's an elderly woman with a broken hip. Ben starts to drive off but stops suddenly to avoid hitting a young woman crossing the street. Dr. Matt looks at her and recognizes Merlyn. When he goes into the hospital, a nurse tells him that the blood supply is low and no help is coming. They are afraid to come to Trinity. Dr. Matt sent some blood samples from the victims to the Centers for Disease Control and now Dr. Billy Peale has arrived to investigate the outbreak. Dr. Matt gives him some files with all the information they have on the outbreak and Billy begins examining patients. He calls for plasma for one man and then goes on to the next patient. When he sees Lucas take the plasma away from the man and tell him he's going to die for refusing him, Billy runs over and stops Lucas. He puts a hypodermic needle against Lucas' neck and tells him never to touch his blood supply again. Lucas gives him the evil eye as he walks away.
Later, Dr. Matt and Billy discuss the situation in Dr. Matt's office. Dr. Matt opens the window in his office and looks out into the hall A man in a wheelchair just outside jumps up throws himself at the window. He is bleeding and smears the blood onto the window, then writes a word in the blood. As the man is being wrestled back into his wheelchair, Dr. Matt walks out into the hall and sees that the man wrote the word "Repent." He then hears a high pitched sound that causes an intense pain in his head.
As Billy is walking from house to house asking questions, he sees Lucas leave E. A. Tippett's house. Inside the house, Merlyn is talking to E. A. He is still seeing blood everywhere and Merlyn is trying to convince him not to help Lucas. Billy knocks at the door and, when no one answers, he walks in. He hears E. A. scream and he runs upstairs. E. A. is bleeding and Billy tells him they'll get him fixed up.
Gail goes to Lucas' office to complain about a newspaper article that denies there is an epidemic. As a reporter, she thinks the article gives her profession a bad name. Lucas tells Gail he doesn't care about truth or integrity. When she asks what he does care about, he replies "You." He tells her he thinks about what it would be like with her. When she answers that she does, too, he touches her face. Ben interrupts at that moment to tell him something is going on at the boarding house. When Lucas arrives at the boarding house, Dr. Matt is quoting scripture and bleeding from the ears. Lucas tells Caleb to leave the room. Lucas puts his hand on Dr. Matt's shoulder and walks him outside as an ambulance pulls up. We next see Dr. Matt locked in a padded room. Lucas and Billy are watching him and talking. When Billy tells Lucas he saw him coming out of E. A. Tippett's house, Lucas asks if Billy thinks he made E. A. sick. Billy replies that he thinks Lucas is the missing link.
Gail can't get her conversation with Lucas out of her head so she goes to Lucas. As they begin to make love, we see Merlyn at the river. She puts her hands in the water and turns the river red with blood. We next see Lucas carrying Gail into the hospital. He tells Billy to make sure she gets better and Billy says he can do that but then Lucas will owe him.
Selena meets Billy outside the hospital. She tells him to look out for Lucas but he's not worried. She asks if he has ever looked into the face of evil and he says he'd probably be too busy to notice. She kisses him on the cheek and walks away.
Caleb is watching Dr. Matt sleep when Billy comes in. Billy lets Caleb go into the room and talk to him. Caleb puts his hand on Dr. Matt's shoulder and tells him everything is going to be all right Then Caleb runs out of the room.
Billy goes to see Lucas in his office. He thinks Lucas is the link to the source of the epidemic and wants to take a blood sample. "I give you my blood, you'll be giving me yours", Lucas warns. Billy takes the blood to send to Atlanta for testing.
Lucas and Ben drive to the bridge in the middle of the night. Lucas gets out and Ben drives on. Lucas calls to Merlyn and begins talking to her. He starts to ask for her help but changes his mind. Merlyn appears and Lucas tells her that he knows her job is to keep people on the straight and narrow. He's been there, he says, and he knows it's easy to get carried away and start to fall. Merlyn replies that he's the one who's fallen. When he tells her he can show her the pitfalls to avoid, she says that she knows what to do and she makes Lucas bleed from his eyes. He puts his hands to his face and when he lowers them again, Merlyn has gone and his eyes have quit bleeding.
Caleb is saying his prayers and he tells God that Gail and Dr. Matt didn't do anything to deserve getting sick. Merlyn appears and tells him that isn't true. Dr. Matt lied for Lucas and Gail laid down with him. Caleb realizes that Merlyn is the cause of the plague. He asks what has happened to her and she replies that she was told to punish the wicked. Caleb tells her he's been talking to Lucas and asks if she's going to make him sick, too. She says she won't hurt him because she loves him. Caleb asks Merlyn to love everyone.
As the sun comes up, Merlyn is at the river. She kneels down and takes the blood out of the river. Caleb smiles when he sees what she has done.
Billy walks up to a plane and a man hands him a cooler full of plasma. Lucas appears and asks if he is leaving, but he says no, he's staying to collect the favor Lucas owes him. Lucas watches him as he walks over to Selena's car.
Back at the hospital, Dr. Matt has recovered and is talking to Gail. After he leaves, she falls asleep. Lucas appears and kisses her on the forehead as she sleeps.