Louis Koo plays 009, or translated literally from its aural pronunciation, double-O Dog. He's one of 12 special Royal Bodyguards of a simpleton Emperor (Liu Yiwei) who named these 12 guards after the Chinese Zodiac, hence 9 translated to Dog. Unlike his peers, Dog is a scientist, and relies pretty much on his brains and fantastical gadgets to protect his Majesty from evil ninja assassins.
| Actor | Role |
|---|---|
 Louis KooRoyal Dog | Royal Dog |
 Barbie HsuFaithful | Faithful |
 Louis Fan Siu-WongLord Unicorn | Lord Unicorn |
 Sandra Ng Kwan-YuEmpress | Empress |
| YYang JiangForbidden City Cop | Forbidden City Cop |
 Liu YiweiEmperor | Emperor |
 Song JiaPrincess Rainbow | Princess Rainbow |
 Tong DaweiRoyal Tiger | Royal Tiger |
 Lam Tze-ChungRoyal Pig | Royal Pig |
 Shi ZhenlongNot listed | Not listed |
 Law Kar-YingNot listed | Not listed |
 Bryan LeungNot listed | Not listed |
 Kingdom Yuen King-TanNot listed | Not listed |
 Mo MeilinNot listed | Not listed |
 Lee Kin-YanNot listed | Not listed |
 朱峰Not listed | Not listed |