|This article is about a/an episode in Zyuden Sentai Kyoryuger.|
Zoom! Plezuon's Back (ズオーン！かえってきたプレズオン Zuōn! Kaettekita Purezuon) is the twenty-first episode of Zyuden Sentai Kyoryuger. It marks the debut of Doctor Ulshade/Kyoryu Violet, his granddaughter Yayoi and his partner, Zyudenryu Plezuon.
At the Spirit Base, the Kyoryugers are notified that the ninth Zyudenryu, Plezuon, is returning from space alongside its partner Kyoryu Violet. However, Plezuon is attacked while re-entering Earth's atmosphere. Arriving at the seaside crash site to find it has crashed into the ocean, the Kyoryugers are attacked by the Zetsumates who the Deboss Army had resurrected to stop Plezuon's return. As the others deal with the Zetsumates and their Deboss MetsuBall attack, Kyoryu Red attempts to reach Plezuon but is immediately swarmed by Zorima. Luckily, he is saved by Kyoryu Violet who reveals that Plezuon has entered their undersea base before he tells Kyoryu Red to aid his friends as they escape the Zetsumates.
With Torin guiding them, the Kyoryugers arrive at the Plezuon Lab where they meet the eccentric Doctor Ulshade and his granddaughter Yayoi. Feeling that they have heard his voice before, the Kyoryugers learn that Ulshade is the inventor of the Gaburivolvers before Daigo asks him where Kyoryu Violet is. But before Torin can reveal who Kyoryu Violet is, he senses the Zetsumates resuming their attack to lure the Kyoryugers out.
Using multiple MetsuBalls to disarm the Kyoryugers, the Zetsumates have the upper hand before Ulshade arrives and reveals himself as Kyoryu Violet. But due to Violet throwing his back out during the ending segment of his introduction, the Kyoryugers are forced to protect Kyoryu Violet before Torin takes him to safety while they intercept a MetsuBall and use it to defeat the Zetsumates.
With Debo Nagareboshi enlarged, Kyoryu Violet gives Kyoryu Red the Plezuon Zyudenchi, as he intended to give to the Kyoryugers earlier, to launch Plezuon to battle. Taking the fight to space, Plezuon transforms into Plezu-Oh to destroy Debo Nagareboshi. Despite this setback, Chaos reveals an ulterior motive as he requests Dogold's aid while contacting the others and the surviving Zetsumates to find Plezuon Lab and destroy it.
- Daigo Kiryu (桐生 ダイゴ Kiryū Daigo): Ryo Ryusei (竜星 涼 Ryūsei Ryō)
- Ian Yorkland (イアン・ヨークランド Ian Yōkurando): Syuusuke Saito (斉藤 秀翼 Saitō Shūsuke)
- Nobuharu Udo (有働 ノブハル Udō Nobuharu): Yamato Kinjo (金城 大和 Kinjō Yamato)
- Souji Rippukan (立風館 ソウジ Rippūkan Sōji): Akihisa Shiono (塩野 瑛久 Shiono Akihisa)
- Amy Yuuzuki (アミィ結月 Amyi Yūzuki): Ayuri Konno (今野 鮎莉 Konno Ayuri)
- Utsusemimaru (空蝉丸): Atsushi Maruyama (丸山敦史 Māruyama Atsūshishi)
- Wise God Torin (賢神トリン Kenjin Torin, Voice): Toshiyuki Morikawa (森川 智之 Morikawa Toshiyuki)
- Doctor Ulshade (ドクター・ウルシェード Dokutā Urushēdo): Shigeru Chiba (千葉 繁 Chiba Shigeru)
- Yayoi Ulshade (弥生ウルシェード Yayoi Urushēdo): Marie Iitoyo (飯豊まりえ Iitoyo Mari)
- Many-Faced High Priest Chaos (百面神官カオス Hyakumen Shinkan Kaosu, Voice): Takayuki Sugō (菅生 隆之 Sugō Takayuki)
- Joyful Knight Candelilla (喜びの戦騎キャンデリラ Yorokobi no Senki Kyanderira, Voice): Haruka Tomatsu (戸松 遥 Tomatsu Haruka)
- Raging Knight Dogold (怒りの戦騎ドゴルド Ikari no Senki Dogorudo, Voice): Satoshi Tsuruoka (鶴岡 聡 Tsuruoka Satoshi)
- Sorrowful Knight Aigaron (哀しみの戦騎アイガロン Kanashimi no Senki Aigaron, Voice): Yū Mizushima (水島 裕 Mizushima Yū)
- Funfilled Spy Luckyuro (楽しみの密偵ラッキューロ Tanoshimi no Mittei Rakkyūro, Voice): Ai Orikasa (折笠 愛 Orikasa Ai)
- Debo Hyogakki (デーボ・ヒョーガッキ Dēbo Hyōgakki, Voice): Kenji Nomura (乃村 健次 Nomura Kenji)
- Debo Viruson (デーボ・ウイルスン Dēbo Uirusun, Voice): Eiji Takemoto (竹本英史 Takemoto Eiji)
- Debo Nagareboshi (デーボ・ナガレボーシ Dēbo Nagarebōshi, Voice): Kazuki Yao (矢尾 一樹 Yao Kazuki)
- Kyoryu Red - Pukuptor, Plezuon (Battle Mode)
- Kyoryu Black - N/A
- Kyoryu Blue - N/A
- Kyoryu Green - N/A
- Kyoryu Pink - N/A
- Kyoryu Gold - N/A
- Kyoryu Violet - N/A
- As part of Super Hero Time, this episode aired alongside Kamen Rider Wizard episode 43, The White Wizard's Secret.
- Viewership: 4.4%
- This is the first time since the first episode where a Kyoryuger debuts and transforms in the same episode.
- The Deboss Jump that the Zetsumates did and the MetsuBall manerver harkens back to Taiyo Sentai Sun Vulcan.
- The "New Power Operation" used later in the MetsuBall is similar to the second-phase of Gorenger Storm used by the Gorengers, where they would add a slight gimmick to the move.
- Kyoryu Violet's jump containing the sound "Toh!" has a similarity to the jump of every Showa-era show like Kamen Rider, Gorenger and many more.
Zyuden Sentai Kyoryuger Volume 6 features episodes 21-24: Brave 21: Zoom! Plezuon's Back, Brave 22: It Can't be! Deboss Revived, Brave 23: Stand! Bakuretsu Kyoryuzin and Brave 24: Burn! Seven Kyoryugers. 
- Powers From the Past - Power Rangers counterpart in Dino Charge. See comparison page. (Yayoi Ulshade's debut)
- World Famous! (In New Zealand) - Power Rangers counterpart in Dino Charge. See comparison page.
- Deep Down Under - Power Rangers counterpart in Dino Charge. See comparison page. (Plesio Zord Debut)
- TV Asahi's official preview for ｢ズオーン！かえってきたプレズオン｣
- Toei TV's official episode guide for ｢ズオーン！かえってきたプレズオン｣