|This article is about a/an episode in Kamen Rider W.|
A suspicious woman hires Shotaro to find a Dopant who is running amuck while taking the name "Kamen Rider" as his own.
After finding Philip trying to train like a boxer through weight-loss hell tactics in the RevolGarry's cockpit after listening to Wakana, seeing a tiny dinosaur robot from his past, the Narumi Detective Agency gets a new client named Fuyumi Aso who asks them to find a Kamen Rider. Thinking it was easy, they learn that the "Kamen Rider" is actually an impostor who has gone on a crime spree and Shotaro takes the case to get to the bottom of it after learning more at the site of culprit's robbery on an armored truck.
Using the Bat Shot, Shotaro finds the culprit Dopant riding a motorcycle to attack the next armored truck and he arrives as Kamen Rider Double in time to stop the attack as the Arms Dopant flees from the scene.
After losing the Arms Dopant, Double finds a small scrap of metal left behind. Later, Akiko and Shotaro confront Fuyumi about her connection to the Dopant and she reveals that she is one half of the Twin Rose cat burglar team, and her partner Kenji Kurata is the Arms Dopant. Despite being lied to, Shotaro still accepts the case on the condition that Fuyumi turns herself in. As Shotaro explains to Akiko his personal reasons for going after the Arms Dopant, Philip has trouble searching for Kurata's hideout until Akiko identifies the piece of metal as being part of an apple-shape, leading him to the Sherwood Building.
As Shotaro makes his way there, Philip is still troubled by the mystery of why Kurata is pretending to be a Kamen Rider. With Akiko and Fuyumi, Shotaro confronts Kurata and orders him to discard the Arms Memory. Kurata, under the Gaia Memory's influence, refuses to give it up and transforms into the Arms Dopant to face him. Shotaro transforms into Kamen Rider Double and fights the Arms Dopant, until the Dopant gets a call from his client who tells him to spring the trap.
The Arms Dopant calls upon a small army of Masquerade Dopants who capture Akiko and Fuyumi, threatening to kill the former if Double does not revert. Shotaro follows through, while keeping in mental contact with Philip to prepare the Luna Memory, but the Arms Dopant fires a bullet that closes up the right side of Shotaro's Double Driver once the Heat Memory is removed.
After the Arms Dopant reveals his target to be Philip, Shotaro yells at him to run as he staggers out of hiding from the RevolGarry. Managing to dodge fire by the Masquerade Dopants, Philip runs outside where he comes across Saeko, the one who set up the trap. With open arms, Saeko walks towards Philip, and calls him Raito, the "Chosen Child".
- Memory Used:
- Soul - Cyclone, Heat
- Body - Joker, Metal, Trigger
- Half Changes:
- CycloneJoker, HeatMetal, HeatTrigger, HeatJoker
- Shotaro Hidari (左 翔太郎 Hidari Shōtarō): Renn Kiriyama (桐山 漣 Kiriyama Ren)
- Philip (フィリップ Firippu): Masaki Suda (菅田 将暉 Suda Masaki)
- Akiko Narumi (鳴海 亜樹子 Narumi Akiko): Hikaru Yamamoto (山本 ひかる Yamamoto Hikaru)
- Mikio Jinno (刃野 幹夫 Jinno Mikio): Takeshi Nadagi (なだぎ 武 Nadagi Takeshi)
- Ryubee Sonozaki (園咲 琉兵衛 Sonozaki Ryūbee): Minori Terada (寺田 農 Terada Minori)
- Saeko Sonozaki (園咲 冴子 Sonozaki Saeko): Ami Namai (生井 亜実 Namai Ami)
- Wakana Sonozaki (園咲 若菜 Sonozaki Wakana): Rin Asuka (飛鳥 凛 Asuka Rin)
- Kirihiko Sudo/Sonozaki (須藤/園咲 霧彦 Sudō/Sonozaki Kirihiko): Yuki Kimisawa (君沢 ユウキ Kimisawa Yūki)
- Narration, Gaia Memory Voice (ナレーション、ガイアメモリ音声 Narēshon, Gaia Memori Onsei): Fumihiko Tachiki (立木 文彦 Tachiki Fumihiko)
- Kenji Kurata (倉田 剣児 Kurata Kenji): Kōichirō Nishi (西 興一朗 Nishi Kōichirō)
- Fuyumi Aso (麻生 冬美 Fuyumi Aso): Yuri Morishita (森下 悠里 Morishita Yuri)
- As part of Super Hero Time, this episode aired alongside Samurai Sentai Shinkenger episode 43, Act 43:One Last Sword.
- This episode aired on the same day as a rerun of the twelfth episode of Kamen Rider Decade, as part of TV Asahi's re-broadcast of the series from beginning to end at the 6:30 am timeslot.
- Following the initial usage of a Masquerade Memory by a stalker of Wakana, this features the first appearance of the Masquerade Dopants as a full-fledged combatman army.
Blu-ray Box 1 comes with 16 episodes.