Aired in late 2009 by 49 episodes. Shotaro Hidari is a private investigator in the ecologically-minded city of Fuuto who works with his partner Philip to investigate crimes that involve users of Gaia Memories which transform them into monstrous beings known as Dopants. Shotaro and Philip have their own set of Gaia Memories that they use in conjunction with the Double Driver belt, with Philip's mind travelling into Shotaro's body to fight as Kamen Rider Double. With their landlord (and daughter of their mentor) Akiko Narumi, Shotaro and Philip protect Fuuto all while investigator Ryu Terui, joined in their fight and transforms into Kamen Rider Accel, the mystery of Philip's past, his relation to the Sonozaki Family, and their Museum organization are revealed.