Miho is one of the thirteen Kamen Riders in the Rider Fight arranged by Shiro Kanzaki. Miho is a con-artist who seduces wealthy men in order to steal their money and/or valuables. Miho accepted Kanzaki's proposal to join the Rider War for two reasons: to resurrect her sister who was killed by Serial killer Takeshi Asakura, and to get revenge on the serial killer.

Shinji met Miho while she was running from a man she tried swindling. A brief romantic interest in Shinji was shown as the two interacted and were often seen bickering like an old married couple. Though she often berated him, she would still perform acts of kindness toward him (such as tying his shoelaces). Miho was rather dedicated to winning the war, as in one scene she tried to steal Shinji's deck before he realized and told her off.

Miho eventually succeeds in killing Asakura by destroying his deck when he was in blank form after Kamen Rider Ryuga destroyed Genocider and saved her. Asakura was reverted to human form and tried to strangle her, but eventually disintegrated. Miho was glad that she avenged her sister, now with one task finished.

Miho was thankful to Shinji (who was she mistook Ryuga as him) and treated him to dinner. However Ryuga then came out of the mirror and tried to harm her, before he revealed himself. Miho was eventually saved by Shinji, as Ryuki came in the nick of time. They escaped later, and Shinji walking Miho home. Despite having sustained fatal injuries from Ryuga, Miho deliberately acted normally in front of Shinji, not wishing for him to feel burdened from her death. Once he had left her sight, Miho then collapsed on the ground, no longer having the strength to stand. Immediately afterwards, Miho apologized to her sister, having failed to win the Rider War. Soon after, she then spoke to Shinji in her final breath, glad to have him before dying.