Mayumi Hashimoto is entrusted with donations received by the class. When the school day is over, she desperately searches for the envelope containing the money, but cannot find it. Another girl, Aya Kuroda, shows up with her friends and asks if something's wrong. The next day, Mayumi has replaced the money, but Aya says that Mayumi owes her for helping her do so and then blackmails Mayumi into buying the group drinks. Later, two students walk by discussing the Hell Correspondence, a mysterious website that is only accessible at midnight and gets revenge for the user at the cost of the user's soul. The bullying continues and Mayumi's mother mentions that money is going missing. Mayumi accesses the Hell Correspondence, but does not submit Aya's name.
The next day, Mayumi overhears rumors about her being seen downtown at night, blowing off her studies and is called to the staff room by her teacher, Mr. Kado, to discuss the rumors with her teacher, Mr. Kado. Mayumi returns home sporting a swollen cheek and submits Aya's name to the Hell Correspondence, receiving a text message saying that her grievance has been heard. After being bullied the next day, Mayumi decides that the Hell Correspondence was a hoax. After arriving downtown that evening, Mayumi spies a mysterious red-eyed girl about her age in the alley nearby. One of Aya's friends pushes Mayumi into a young man and Aya takes a picture of the two for further blackmail. Mayumi attempts suicide by jumping off a building, but is intercepted by the mysterious girl, who brings her to a landscape locked in perpetual sunset. The mysterious girl introduces herself as "Ai" and offers Mayumi a straw doll and tells her that if she wants revenge, she only needs to untie the red thread around the doll's neck and Ai will ferry Mayumi's tormentor straight to Hell. Ai then warns Mayumi that if she does so, she will also go to Hell after she dies, giving Mayumi a vision of flames shooting up around her.
- Ai: If you truly wish revenge, just untie the scarlet thread from his neck. Pulling the thread binds you into a covenant with me: I will ferry the soul of your tormentor straight into the depths of Hell. However, once vengeance is served, you will have to deliver on your end of the bargain. There always has to be a price. When you die, your soul will also belong to Hell. You will never know the joys of Heaven. You will be left to wander through a world of pain and agony, there to remain for all eternity.
Mayumi awakens from the vision on the sidewalk. The next day, Aya leaks the photo, resulting in Mayumi being called to the staff room and threatening her prospects for high school. Mayumi pulls the thread.
- Voice: Your grievance shall be avenged!
In the sunset realm where Ai is putting on a flower patterned Kimono inside a straw-roofed hut. Ai goes to fulfill her end of the bargain aboard a fiery carriage with an enraged face one wheel. Aya receives a text message from Mayumi, who leads her into the darkened school building and then runs off. Aya gives chase, but wanders into a room full of faceless students with class in session. Spotting Mayumi again, she gives chase but loses sight of Mayumi, eventually wandering outside, revealing the school grounds in broad daylight. A volleyball lands near Aya and the volleyball team asks her to get it for them. Aya picks up the ball only to find herself holding a skull and runs back into the building, once again at night. Aya runs into Mr. Kado, who says that he has also been seeing strange things and leads her to a wall that is pulling her friends in. Aya screams and runs away as "Mr. Kado" reveals himself to be an elderly bald man and puts on a fedora. Aya escapes to the front entrance, only to find herself in her homeroom when she opens the door. There, she sees herself stealing the class donations. The room is suddenly lit by a sunset as Mayumi accuses Aya of the theft which Aya denies, saying that nobody saw it. In response, a voice says "Actually, I saw it...". Aya looks up and is shocked to see a giant eye on the ceiling. Aya screams, but then sees a woman in a blue kimono standing where Mayumi was a moment before.
- Woman: Well, have you learned your lesson yet?
Aya then sees the old man and a young man standing behind her. Aya accuses the three of pulling a prank. The woman reveals part of her skull as she calls Aya out for being hypocritical. Aya refuses to admit her wrongdoing and Ai appears, reciting an incantation:
- Ai: O pitiful shadow lost in the darkness, bringing torment and pain to others. O damned soul wallowing in your sins, perhaps it is time to die.
The flowers on Ai's kimono fly at Aya, who then wakes up on a boat in a dark river with a large Torii gate in the distance. Aya sees Ai rowing the boat and tries to get up, but is restrained by hands that sprout out of the boat itself as Ai ferries the boat through the gate of Hell.
- Ai: This is vengeance, so I am to ferry you to Hell.
Back in the world of the living, all of the trouble involving the stolen money has been cleared up, but Mayumi sees that a black flame symbol has appeared on her chest and recalls that she sold her soul to get where she is now. A candle with Mayumi's name is lit and the episode ends.
This episode contains examples of:
- Alpha Bitch: Aya. See The Bully below.
- Bishōnen: The young man from the Hell banishment sequence.
- Blackmail: Aya does this to get favors out of Mayumi.
- The Blank: A whole classroom full of them during the Hell banishment sequence.
- Break the Cutie: Aya's cruel behavior drives Mayumi to tears, especially when it puts Mayumi's future in jeopardy after she's chewed out by the school for the photos Aya took.
- The Bully: Aya not only uses the Stock Shoujo Bullying Tactics on Mayumi but has implied to hit her as well.
- Compensated Dating: Mayumi is blackmailed into this by Aya.
- Dark World: The Hell banishment takes place in a darkened version of the school that switches between day and night.
- Establishing Series Moment: This episode establishes the formula for the series.
- Eye Spy: The eye on the ceiling was the young man's left eye, which is covered by hair when he appears in person.
- Fire and Brimstone Hell: Ai gives Mayumi a vision of one.
- Girlish Pigtails: Mayumi.
- Interrupted Suicide: Ai stops Mayumi's suicide attempt in order to make the deal with her.
- Mind Rape: After Mayumi pulls the thread, before Aya is banished to Hell she is subjected to a Mind Rape specifically tailored to her misdeeds: she's a school bully who stole the class money to make Mayumi think she lost it so she could blackmail her, and she plays other nasty tricks. So as punishment, Aya is transported to a "horror movie"-style version of her school where the demonic children torment her with a bunch of "pranks", to show Aya what it's like to be on the receiving end.
- Never My Fault: Ai's minions give Aya a chance to repent for her misdeeds, but Aya refuses, writing off her cruel treatment of Mayumi as just "kid stuff", and refusing to own up to her theft of the money.
- No Name Given: Ai's minions aren't named during the episode itself.
- Red Sky, Take Warning: The sunset realm has an ordinary sunset sky when Ai rides forth, but it's blood red when Mayumi receives the straw doll.
- Technicolor Fire: The flames in Mayumi's vision of Hell are blue.