- "I want to use it to open her eyes."
- — Tsukasa —
Twilight Eye is the thirteenth episode of .hack//SIGN.
The episode begins with Subaru quoting the original BBS post about the Key of the Twilight to BT. They discuss the possibility of Tsukasa's existence being due to the power of the Key. Later, BT is confronted by Bear over her divulging the private information about Tsukasa to Crim and Subaru. BT does not apologize for her actions. Bear then informs her that he and Mimiru are also searching for the Key and that they will consider BT and Crim to be rivals in the search.
Elsewhere, Mimiru meets up with Sora, who passes on information from Helba. Helba tells them that with the three keywords to the Legendary Land and Tsukasa's power, they won't need to wait for the Twilight Eye to open. Sora then tells Mimiru about the real Tsukasa who is comatose. Mimiru confronts Bear about the matter, angry that this information was withheld from her for so long. The anger subsides soon enough, and she agrees to help in the search.
BT discusses the search with Crim and focuses on finding out what is necessary for the Twilight Eye to open. In her opinion, it is found on a special field where some special conditions must be met. Crim agrees and leaves it up to her to find out what is needed.
Back in Dun Loireag, Bear tells Mimiru that he believes Tsukasa may be a girl in real life. Bear also wonders about what the so-called Legendary Land is and also realizes that their movement relies mostly on Tsukasa. As if on cue, Tsukasa appears and explains his desire to search for the Key. When asked what he wants to use it for, he says he wants to open the eyes of the sleeping girl.
Crim meets with Subaru and tells her he knows the location of the Twilight Eye. He then asks if Subaru wants the Key, to which she replies that she does. Crim then promises to deliver the Key to her.
At Mac Anu, Bear, Mimiru, and Tsukasa meet with Silver Knight and ask what he knows about the Legendary Land. He replies that there are at least three Legendary Lands and that they are linked to the backstory of The World. He also says that although he doesn't know the keywords, the path is blocked anyway. Bear leaves the game to investiage outside, leaving Tsukasa and Mimiru by themselves.
BT meets with Sora and tells him that she may have found the location of the Twilight Eye and that she may be able to meet with the original author of the Key of the Twilight post tomorrow. Meanwhile, Bear is called to a dungeon at a late hour and is met by Helba.
At Hulle Granz Cathedral, BT and Crim meet and agree that this is the location of the Twilight Eye, as it not only is accessible by the words "Hidden" "Forbidden" and "Holy Ground," but was once originally accessed by the words "Navel of Lake," words that were found in the original message.
Bear tells Mimiru about his encounter with Helba and how he was given the keywords to the Legendary Land in exchange for revealing what information is found there. The two now wait for Tsukasa, who has the power to take them there. Tsukasa himself disobeys Macha for the first time by leaving to find the Key.
When Crim wonders how to find the Twilight Eye now that they have found the area, BT tells him that the answer is basic: it can be found by using magic that discovers hidden elements and reveals them. As Sora watches from the shadows, BT uses her innate ability as a Wavemaster (which basically has the same functions as a Fairy's Orb) and causes the mist surrounding the cathedral to disperse and the Twilight Eye to open. In addition, a hidden bridge leading to a red Chaos Gate also appears.