Toku-Hen

Story Line
Plot begins with a sad, depressed Keiichi who looks over at the calender that says July 16. His phone then rings as he hesitates to answer it, as he actually answers it, he is surprised to hear Mion on the other line. Mion is walking down the Hinamizawa city streets as she cheerfully talks to Keiichi and reminds him that it's their one month anniversary.

As Mion's walking down the streets, she pauses from talking on the phone to wave cheerfuly at Rena, who, unknowingly to her, is going through her worst stage of the syndrome yet as in clawing at her throat and the whole nine yards. Since Mion and Keiichi got together, Rena's sorta become the "odd man out" and is seen as burden. Instead of commenting on Rena's sad appearance, the distracted Mion goes back to her phone and tells Keiichi to meet up with her at a certain apartment at 6 o'clock for a surprise.

Keiichi is caught completely off guard by this whole ordeal and just stares at his phone in a mysterious form of amazement. While he sits there looking at his phone, Mion goes into the hotel room and begins to set it up with decorations as a surprise as well as with a cake and everything. Keiichi then decides to run over there as quickly as he can, but when he gets to the apartment, it's blocked off by yellow tape.

Oiishi see's him and is about to question him when Keiichi rushes past him and into the room, only to see it completely destroyed as well as a body with a blanket drapped over it. Keiichi at first doesn't believe what he sees is what he thinks it is, until he see's some long green hair peeking out from under the blanket. Keiichi then freaks out and tries to go to the body to try to help Mion with the idea that she isn't dead when Oiishi stops him and pulls him out of the room, preventing him from going in the room.

Keiichi is forced to stay in the lobby as he remains a mess. He then comes up with the idea of using the hotel phone to call the room. As he does, it's picked up and he's shocked to hear Mion on the other line. He then realizes this is his chance to save her as he begins to anxiously tell her not to answer the door at all costs. At that very moment the someone knocks on the door. Mion then smiles, thinking that it's Keiichi knocking on the door as a joke, and puts the phone down to go open it.

When Mion opens the door however, instead of seeing Keiichi, she see's a dark and scary Rena with her cleaver or whichever weapon of choice at hand. Rena then accuses Mion of stealing her friendship with both Mion and Keiichi and ends up killing Mion, all the while Keiichi is listening through the phone. Rena then looks over at the calender, commenting on how it's only the 15th and leaves, unaware of Keiichi's new knowledge.

Keiichi, both traumatized and vindictive, rushes over to Oiishi and tells him that he thinks it was Rena. Oiishi and the others look into it, and Rena is eventually caught and sent to jail. Mion's funeral eventually occurs and as it does, Keiichi is seen as the last person to stand there as he waits for everyone to go. Who ever is Keiichi then has the option of killing himself there beside her grave, moving on, or well, whatever they want as they end the plot.

Maebara Keiichi
The tragic protagonist that is dating Sonozaki Mion. He hears his girlfriend get killed and traumatized by her death.

Sonozaki Mion
The 'sacrifical lamb' of Toku-hen. She is dating Maebara Keiichi and unknowingly spurs the wrath of her friend, Rena, which ends with her being killed.

Ryuugu Rena
A friend to both Keiichi and Mion. She suffers from the late stages of Hinamizawa Syndrome, albeit it was unnoticed by her friends. Both the Syndrome and her feelings of lonliness due to Mion and Keiichi's relationship drive her to kill Mion on her and Keiichi's anniversary.

Setting
Toku-hen takes place in the canon setting of Hinamizawa