|This article is about a/an episode in Kamen Rider Ryuki.|
A Dangerous Sign (危険のサイン Kiken no Sain) is the thirty-ninth episode of Kamen Rider Ryuki. It is the debut of Psuedo-Rider Alternative Zero.
- Takeshi tricks his new lawyer into showing him his belongings.
- Ren learns that Hideyuki and Satoru are targeting Yui and confronts both of them.
- Reiko's curiosity about Shinji's behaviour becomes even more stronger as Reiko learns that Shinji knows about Shiro Kanzaki.
- After destroying two monsters, Satoru attacks Shinji from behind.
- Yui is targeted by a monster that was at the Lab at Seimeiin University.
- Yui discovers that the Mirror and Contract Monsters all came from drawings she and Shiro made during their childhood.
At the prison, officers tell Reiko that only Takeshi's attorney can see him. Shuichi offers to be Takeshi's attorney again but the officers refuse as he has been been assigned to another laywer, Kazuyoshi Morimoto. Reiko storms out of the prison. Ren runs into Shiro on the beach and asks about Kamen Rider Odin. Shiro tells him that Odin is no one and that he will always exist until the end. Shiro tells Ren to fight someone. Ren initially refuses but after learning that Yui is being targeted, he seemingly accepts. At the cafe, Shinji tells Tojo to go home early. Ren returns and confronts Satoru about targeting Yui. Shinji tells Ren about the situation. Ren doesn't completely believe him and tells Shinji that helping Satoru would make him get in the way. Kazuyoshi meets up with Takeshi who is tied up and restrained from moving at all. Back at Shuichi's, Goro hands Shuichi information on the other lawyer. Meanwhile, Takeshi talks the Kazuyoshi into bringing his personal belongings to show him. The next morning, Satoru sees the picture of the old Kanzaki household and tells Shinji that he would like to go there. Back at the lab, Hideyuki watches a robotic Monster moving around the mirrors. Kazuyoshi, despite warnings from officers, prepares to show Takeshi his belongings. Shinji and Satoru make there way to the Kanzaki household, but not before they run into Reiko who realizes the house in the picture. Ren visits Hideyuki at the lab and warns him to stay away from Yui. Ren questions Hideyuki's so-called heroics in killing Yui but Hideyuki tells him he wouldn't understand. Just as they are about to enter Mirror World, Hideyuki's family visit him. At the same time, Shinji and Satoru sense a monster while talking to Reiko and run off. They transform and enter Mirror World. Hideyuki's family leaves and Hideyuki explains to Ren the time that he found out about Shiro's plans. They both transform and enter Mirror World. The two monsters attack Tojo and Shinji just as Hideyuki and Ren begin to fight. Back at the cafe, the monster that was hiding in the lab mirrors appears in a photo frame and appears to target Yui. Shinji uses his Survival Card as Yui runs through the streets to escape from the monster. The fight continues between Ren and Hideyuki. However, being able to remember everything through an amazing memory, Hideyuki predicts Ren's attack patterns and begins to fight back. Satoru and Shinji both use there Final Vents and destroy the two monsters. Yui breaks the mirror that is harbouring the monster but he appears in another mirror. Ren activates Survival. Satoru, for apparently no reason attacks, Shinji from behind. Using a Blust Vent as a distraction, Ren escapes to go and save Yui. Yui wakes up in an old warehouse with the monster walking towards her. Suddenly, explosions erupt infront of the monster and Yui remembers back to her childhood when she drew pictures of monsters, including Dragreder. Satoru continues to attack Shinji telling him that people who can't sacrifice one thing should not be Riders at all and that he is exactly like Hajime. Shinji realizes that Satoru feeling sorry for the death of Hajime was just an act to trick him. Satoru kicks Shinji who falls down. The monster chasing Yui seems unharmed by the explosions and shoots missiles from its head at Yui. However, a Mirror Monster jumps in front and absorbs the explosion instead. The Mirror monster chases the Targeting monster away. Takeshi is called in for his meeting with his Kazuyoshi. Meanwhile a group of Mirror Monsters rampage around Mirror World. Nanako catches one's attention while she taking photos of her lizard. It jumps out to attack her.
- Shinji Kido (城戸 真司 Kido Shinji): Takamasa Suga (須賀 貴匡 Suga Takamasa)
- Ren Akiyama (秋山 蓮 Akiyama Ren): Satoshi Matsuda (松田 悟志 Matsuda Satoshi)
- Yui Kanzaki (神崎 優衣 Kanzaki Yui): Ayano Sugiyama (杉山 彩乃 Sugiyama Ayano)
- Shiro Kanzaki (神崎 士郎 Kanzaki Shirō): Kenzaburo Kikuchi (菊地 謙三郎 Kikuchi Kenzaburo)
- Shuichi Kitaoka (北岡 秀一 Kitaoka Shūichi): Ryohei (涼平 Ryōhei)
- Goro Yura (由良 吾郎 Yura Gorō): Tomohisa Yuge (弓削 智久 Yuge Tomohisa)
- Takeshi Asakura (浅倉 威 Asakura Takeshi): Takashi Hagino (萩野 崇 Hagino Takashi)
- Satoru Tojo (東條 悟 Tōjō Satoru): Jun Takatsuki (高槻 純 Takatsuki Jun)
- Reiko Momoi (桃井 令子 Reiko Momoi): Sayaka Kuon (久遠 さやか Kuon Sayaka)
- Nanako Shimada (島田 奈々子 Shimada Nanako): Hitomi Kurihara (栗原 瞳 Kurihara Hitomi)
- Sanako Kanzaki (神崎 沙奈子 Kanzaki Sanako): Kazue Tsunogae (角替 和枝 Tsunogae Kazue)
- Hideyuki Kagawa (香川 英行 Kagawa Hideyuki): Satoshi Jinbo (神保 悟志 Jinbo Satoshi)
- Kazuyoshi Morimoto (森本 和義 Morimoto Kazuyoshi): Shiro Namiki (並樹 史朗 Namiki Shirō)
- Nobuko Kagawa (香川 伸子 Kagawa Nobuko): Mitsuyo Hoshino (星野 光代 Hoshino Mitsuyo)
- Yuta Kagawa (香川 佑太 Kagawa Yūta): Kengo Tajima (田島 健吾 Tajima Kengo)
- Guard: Koichiro Kotani (小谷 公一郎 Kotani Koichirō), Kazuhiro Yoshikawa (吉川 和宏 Yoshikawa Kazuhiro)
- Zelles (ゼール Zēru, Voice), Omegazelle (オメガゼール Omegazēru, Voice), Magazelle (マガゼール Magazēru): Katsumi Shiono (塩野 勝美 Shiono Katsumi)
- Cards used:
- Survive Rekka, Ryuki Survive Final Vent
- Sword Vent, Survive Shippu, Blust Vent
- Final Vent
- Alternative Zero:
- Sword Vent
- Weapons/Powers summoned:
- Dragvisorzwei, Dragon Firestorm
- Winglancer, Darkvisorzwei, Blust Vent
- Crystal Break
- Alternative Zero:
- Sword Vent
- Advent Card appeared before episode's preview:
- Viewership: 9.1%
- This episode aired alongside Ninpu Sentai Hurricaneger episode 36, Scroll 36: Ring and Revenge.
- First appearance of Psyco-Rogue.
- It's revealed that Kagawa had a family, foreshadowing Satoru's dissatisfaction in the next episode.
- Kagawa's henshin pose before his first battle against Knight, throwing the Alternative Deck into the air before grabbing it and inserting it into the belt, is similar to how Takatora Kureshima does during his transformation sequence into Zangetsu 11 years later in Episode 10 of Kamen Rider Gaim.
- Kamen Rider Ryuki DVD Volume 10 features episodes 37-40.
- Kamen Rider Ryuki Blu-ray Volume 3 features episodes 35-50.