- "The plan was to lure out Kite, but the one caught in the trap was just as good, BlackRose indeed."
- — Michi —
Mansion of Terror (恐怖の館) is the fifth episode of .hack//Legend of the Twilight.
Outside of The World, four hackers named Michi, Katsuyuki, Hayato, and Daisuke meet in an apartment. They discuss how their supposedly unstoppable creatures were defeated by a player with the ability to Data Drain. One of them mentions that the only player who possesses that ability is the legendary .hacker Kite. Concerned over Kite's apparent return to The World, they begin to formulate a plan to remove him from the system for good.
In The World Shugo explores a special beach field. Rena and Mireille soon show up and show off their swimsuit items, Mireille's of course is a rare item. They are interrupted when Ouka appears with Sanjuro. Sanjuro tells Shugo and Rena that he needs to talk to them, and leads them to a secluded portion of the field. He tells them that the amount of time they've been playing recently has concerned him, and he fears they've become addicted to the game. He suggests that they stop playing The World, or at least take a break for a bit. A flashback shows that his words were actually from Balmung, who is afraid that Shugo and Rena will soon be drawn into a battle against an unknown enemy. In order to make sure they're 100% committed he asked Sanjuro to test their resolve to keep playing The World.
Shugo tells Sanjuro that he still has a promise to fulfill to the girl who gave him the Twilight Bracelet. She told him that he alone had the power to save The World, and Shugo wants to figure out exactly what she meant. Realizing Shugo is talking about Aura, Sanjuro accepts that both Shugo and Rena are committed to playing the game. He prepares to leave, but warns them that if they encounter anything out of the ordinary that they should log out immediately and contact him.
Rena and Shugo walk down the beach, where they notice Michi apparently being bullied by three boy (actually Hayato, Daisuke, and Katsuyuki). Shugo and Rena confront the boys, and succeed in scaring them off. Rena comforts Michi, while Shugo retrieves the beach ball item the bullies stole from her. He hands it back to her, unaware that the item is actually a trap designed to steal his Member Address. Having completed her mission, the Michi smiles and warps away. In the real world the four hackers celebrate, stage one of their plan to delete Kite has been completed.
Later, Shugo returns home and finds a new e-mail in his inbox. Opening it he finds what appears to be a garbled message from Aura. Though most of the message is incomprehensible the worlds "Help Me" are clearly visible. Shugo sends the message to Mireille who uses a decoder to reveal the rest of the message. The full message gives the location Δ Cursed Woodland Murderhouse, so Shugo and his party decide to visit there to see what's happening. Sanjuro agrees to come along as well. Together they warp to the field and enter the areas dungeon, which is modeled after a haunted mansion.
Elsewhere Balmung completes his repairs to a field damaged by the hackers. Reki appears and tells him that over 200 bug reports concerning corrupted fields have been reported, and more are continuing to pour in. Balmung tells him to do his best to control things, and prepares to gate out. He is interrupted when several Cobalt Knights gate in. The Knights accuse both Balmung and Reki of being hackers, but their leader Kamui and her assistant Magi soon arrive and recognize them as System Administrators. She informs Balmung that due to his failure to maintain control of the situation the Cobalt Knights have been called in to solve things. After placing an observation shield around the field the Knights gate out. Reki comments that the Knights have been relentlessly hunting and deleting nonstandard players recently, and Balmung worries that Shugo will soon become a target.
Shugo and his party enter the mansion and begin to explore. The entire party fails to notice Komiyan III as he spies on them from a secret room, having followed them from Mac Anu. Rena seems exceptionally jumpy, causing Shugo to remember how easily frightened she was as a kid. He teases her a bit, causing her to go off on her own to prove her bravery. She soon loses track of the rest of the party, and finds herself alone and lost in the dungeon. She accidentally triggers a trap which frightens her. Rena's screams draw Komiyan, who missteps and finds himself caught up in a large rug. Mistaking him for a monster Rena attacks him and knocks him out of a nearby window.
Shugo soon arrives, but finds that Rena has already moved on. Sanjuro tells him that it's dangerous for her to be alone, he needs to find her quickly. Unfortunately the path ahead is filled with monsters. Shugo and his party begin to fight, but for every monster they kill another springs up. Sanjuro yells at Shugo to find Rena so they can leave the dungeon immediately.
Deeper in the dungeon Rena regrets going off on her own. She's still lost, and can't even remember which way is the way back out. A small firefly draws her attention, and she begins to follow it through the dungeon, eventually reaching a room modeled after a torture chamber. Without warning the door behind her slams shut, and the firefly transforms into Aura, a disembodied voice says that the trap had been made for Kite, but that BlackRose will work just as well. Aura then lifts her head, revealing that she was nothing more than an illusion to disguise a Data Bug. She tries to fight it, but finds that all of her attacks are repelled. With a single hit the monster reduces her HP to 0. Shugo suddenly arrives, bursting down the door. Using Data Drain he is able to defeat the monster. The rest of his party arrive shortly afterwards.
Mireille tries healing Rena, but finds that none of her spells are effective. As the party watches Rena fades away, despite their best efforts to revive her. In the real world Shugo tries calling Rena, unaware that she's fallen unconscious.
- Shugo loses his tooth in this episode after Katsuyuki hits him in the face with a beach ball.
- At the end of the episode, as Shugo tries to call Rena, viewers can hear that her cell phone has an instrumental version of "Obsession" (the opening theme of .hack//SIGN) as a ringtone.