Takeshi Hongo is a promising young man with a passion for motorcycle racing. However, his dreams are suddenly ruined when he gets kidnapped by Shocker, the evil secret organization planning to dominate the world. After being remodeled into a cyborg, Takeshi escapes and swears to protect the world from the inhuman monsters.
The best episode of "Kamen Rider" season 21 is "Medal, Underwear, Mysterious Arm", rated N/A/10 from 0 user votes. It was directed by Ryuta Tasaki and written by Yasuko Kobayashi. "Medal, Underwear, Mysterious Arm" aired on 9/5/2010 and is rated NaN point(s) higher than the second highest rated, "Greed, Ice Candy, Present".
A mysterious arm reawakens the Greeed from their slumber and decides to use Eiji Hino, a cheerful wanderer, as his means of getting back what he desires as Kamen Rider OOO.
Director: Ryuta Tasaki
Writer: Yasuko Kobayashi
Ankh explains the Greeed and the purpose of the Medals to Eiji, even as the human desires to merely use his new power to fight for good instead of for selfish needs.
Director: Ryuta Tasaki
Writer: Yasuko Kobayashi
Ankh becomes troubled when Eiji prevents him from eliminating his possessed body's sister while another Greeed uses a man's gluttony to create more Medals.
Director: Takayuki Shibasaki
Writer: Yasuko Kobayashi
Ankh threatens to leave OOO for Kazari and the Greeed while investigating the evolution of humanity while Eiji tries to find more about Hina.
Director: Takayuki Shibasaki
Writer: Yasuko Kobayashi
Kougami asks for a share of Eiji and Ankh's Medals, while Mezool decides to use Hina's shopaholic classmate to create a new Yummy.
Director: Osamu Kaneda
Writer: Yasuko Kobayashi
Hina confronts Yamano's shopping addiction when her father goes bankrupt while Ankh confronts Kougami about his share deal of the Cell Medals.
Director: Osamu Kaneda
Writer: Yasuko Kobayashi
Eiji tries to research a husband bullied by his wife that is being mocked by Gamel while Ankh follows a lead for a missing Core Medal.
Director: Satoshi Morota
Writer: Yasuko Kobayashi
Eiji gets to the root of the Komoris' problem involving greed and loss of ambition while Ankh fights for survival after a failed confrontation with Uva.
Director: Satoshi Morota
Writer: Yasuko Kobayashi
A serial bomber tied to a nest of Yummies leads to Eiji to reveal his past to Hina and forces him to encounter a strange man he believes is Mezool's victim.
Director: Takayuki Shibasaki
Writer: Yasuko Kobayashi
Eiji must figure the means of stopping the mad bomber and his Yummies to prevent any more lost lives, even with Maki observing the creation of his worker's monsters.
Director: Takayuki Shibasaki
Writer: Yasuko Kobayashi
Eiji's traveler friend becomes manipulated by Uva into becoming famous as he steals others attributes; while Gotou doubts Eiji's effectiveness as OOO.
Director: Osamu Kaneda
Writer: Shouji Yonemura
Eiji teaches a lesson to Tsukuba and Gotou about going forth to gain what is desired; while Ankh tries to figure a way to manage the flying Ageha Yummy using Gamel.
Director: Osamu Kaneda
Writer: Shouji Yonemura
Ankh is at a breaking point with everything surrounding his human host; a highly sought after doctor has been repeatedly removed from the operating room, making her frustration a perfect target for the Greeed.
Director: Hidenori Ishida
Writer: Yasuko Kobayashi
Both Hina's brother and the hospital director are in critical condition after Ankh's detachment and the Yummy attack. Eiji must find both Ankh and the affected surgeon before it's too late.
Director: Hidenori Ishida
Writer: Yasuko Kobayashi
Ankh finds one of his core medals; Gotou is transporting a truck full of medals to Doctor Maki; Kazari appears to Ankh and Eiji, telling them that Hina is in Gotou's truck.
Director: Satoshi Morota
Writer: Yasuko Kobayashi
Eiji learns about how the Greeed were born; Gamel searches for Mezool; Kamen Rider Birth joins the fight.
Director: Satoshi Morota
Writer: Yasuko Kobayashi
The Greeed take an interest in a girl who wants to get better at kendo; Ankh takes an interest in Kamen Rider Birth; Hina gives both Eiji and Ankh gifts for saving her.
Director: Takayuki Shibasaki
Writer: Yasuko Kobayashi
Eiji and Ankh try to find out the reason that the Yummy split in two, but Kamen Rider Birth is one step ahead of them.
Director: Takayuki Shibasaki
Writer: Yasuko Kobayashi
Kougami tries to give Eiji one of Ankh's medals, but he refuses; a face from the detective's past shows up at Cous Coussier; thanks to Kazari, a criminal that the detective put away is on the streets and looking for revenge.
Director: Hidenori Ishida
Writer: Yasuko Kobayashi
Ankh tricks Kazari by telling him that Eiji knows where his last medal is and then chases after Hina who has his own medal; Date and Gotou discuss the skills need to be Kamen Rider Birth; Kougami changes his mind and sends Ankh's medal to Eiji.
Director: Hidenori Ishida
Writer: Yasuko Kobayashi
The Cous Coussier gang runs into a young boy getting attacked for telling off a man for littering, learning that it's something he picked up from his father; the Greeed creates a Yummy from the desire to help people.
Director: Ryuta Tasaki
Writer: Nobuhiro Mouri
Susumu lets his desire for justice get out of hand and it's up to Eiji to stop him before it's too late; Gotou and Takashi have a heart-to-heart conversation about their ideals.
Director: Ryuta Tasaki
Writer: Nobuhiro Mouri
Kazari is drawn to the vanity of woman whose sister takes all the credit for her work.
Director: Satoshi Morota
Writer: Yasuko Kobayashi
Eiji is head over heels for Yuumi and it's up to Date to save his old friend before she does something that she'll regret.
Director: Satoshi Morota
Writer: Yasuko Kobayashi
Ankh is acting more standoffish than usual; a boxer is forced into retirement just before a big match and is captured by a bird Yummy.
Director: Takayuki Shibasaki
Writer: Yasuko Kobayashi