"This Episode Sucks" is an episode of the dramedy Psych which makes suitable viewing for Halloween. It was originally aired in the US in 2011.
Created by Steve Franks and broadcast on the USA Network, Psych is an American detective comedy-drama (also known as a "dramedy") which follows Shawn Spencer (played by Jame Roday), a young crime consultant who pretends to have psychic powers, when instead he is simply using a heightened sense of observational skills and detective instincts above the rest of the Santa Barbara Police Department. He chose to pretend to be a psychic after numerous tips he called in to the police department made them suspicious as to his overt knowledge of the crimes. Shawn is followed around by his best friend and reluctant partner, Burton "Gus" Guster (played by Dulé Hill), as well as his father, Henry Spencer (played by Corbin Bernsen) who is a retired member of the police force, who also taught Spencer to be a super sleuth.
The episode begins with head detective Carlton Lassiter in a bar one night. Suddenly, a young woman named Marlowe enters the bar and sits next to him. Lassiter is attracted to Marlowe and the two hit it off immediately. Marlowe buys Lassiter a drink and mentions that he is a cop. When Marlowe hears this, she excuses herself to the bathroom. Lassiter waits for her to come back but, after several minutes, Lassiter goes to check on her, to see if she is okay. Unfortunately, she is not in the bathroom but the window is open, probably meaning she stood him up and climbed out the window. Lassiter is heartbroken.
The next morning, Lassiter, Shawn Spencer, Burton "Gus" Guster, Juliet O'Hara, and Buzz McNab arrive at a crime scene, where a man has been murdered. Lassiter secretly asks McNab to find out where Marlowe is. Lassiter then goes to examine the body. He sees puncture wounds on the man's neck and wrist. He suddenly sees the same necklace Marlowe was wearing the previous night, which makes him fear that Marlowe was the murderer. Shawn, who is talking to Gus, points out that the body is extremely pale for a person who has only been deceased for a short amount of time. Gus tells Shawn that the only way for that to happen, would be if the murder victim had lost a lot of blood. With that fact, and the puncture wounds, Shawn announces to everybody that the murderer is a vampire. Lassiter, who does not want to believe that Marlowe is the murderer, uncharacteristically agrees with Shawn's theory.
The autopsy proves what Gus said is right, the victim has suffered from severe blood loss. This furthers makes Shawn belief that it was a vampire who murdered the man.
Shawn, Gus and Juliet, go to a vampire themed bar, to figure out who murdered the man. Juliet tries to convince Shawn that his vampire theory is crazy. They interrogate the bartender, asking if he dealt with any unusual customers lately. The bartender replies, that he recently received a call asking for a pint of blood. Juliet asks if they could trace the number and they find an address.
Meanwhile, Lassiter finds Marlowe's house. Marlowe is happy to see him, and surprised that he found her. She admits that the reason she stood him up was because she was nervous because she liked him. As the two sit on the couch together, there is a knock on the door. It is Shawn, Gus, and Juliet. They reveal that the call for blood came from that house's phone. They accuse Marlowe of murdering the man. However, Marlowe reveals that she has three male roommates, so one of them probably made the call. They decide to interrogate one of Marlowe's roommates, named Lunien. However, Lucien has a good alibi, so they rule him out.
Shawn suddenly remembers an address he saw at Marlowe's house. He, Gus, and Juliet go there. It turns out to be a blood bank. They see a cat go in, which Shawn is convinced is the vampire murderer who has shape shifted. They follow it in and soon see a hooded figure. Shawn is convinced that this is the vampire. Even Juliet admits that it is strange how fast the figure was able to flee the scene. Shawn notices a fingernail in the debris of the break-in and immediately makes the connection that Marlowe had the same exact fingernails.
The three arrive back at Marlowe's house, and find her sleeping with Lassiter. Shawn tells Lassiter about the fingernail. He then searches her apartment and finds a bag of blood. Much to Lassiter's disappointment, he has no choice but to arrest her.
While Marlowe is in custody, they get another call saying a man has been drained of blood, thus proving that Marlowe was not the killer. Shawn soon discovers that both victims' blood was O negative. Gus points out that this is a very rare blood type. Juliet joins them and Shawn tells her about the break in the case. Juliet remembers that Lassiter has O negative blood, so the murderer will probably soon come after him.
Juliet's theory is correct. A man, who introduces himself as Adrian and is Marlowe's brother, comes to Lassiter and sets up equipment to drain his blood. Adrian explains to Lassiter that he has a disease, which means that he needs blood every week, or else he will die. However, his insurance stopped funding him for blood and he now has to steal it, which is difficult because his blood type is very rare. He tells Lassiter that he sent Marlowe to him to drug him and drain his blood. However, she did not because she fell in love with him. Suddenly, Shawn, Gus, and Juliet come in. They save Lassiter and Adrian is arrested.