Sakaen is terrorizing Fuuto. Where's Rescue Fire? Wait... that's not Sakaen and I'm not watching Rescue Fire. Oh right. This is a story of the half and half Kamen Rider known as Double.
Spoiler
I like the style of the series as it's really a modern look of old detective stories with the detective, the book-smart assistant, and the nearly useless female role. Namiko is just annoying to me. Phillip is a bit interesting and seems to have an ability to move his consciousness into data. I'm not sure about Shoutarou yet but seems to have some brains to be a detective. The villains might be interesting with the family aspect that they seem to have. Dopants are seem to be like drug users in a way.
As for Double, I like it and its ability to switch forms on the fly. Luna's ability was kinda cool and the split Rider Kick didn't really bother me compared to some of the other people. I think Double is off to a good start.