Yataro Sarumaru, nicknamed "Saru" is an average high school boy who daydreams about idols but otherwise has no luck with girls. While working with his father, a locksmith in Asakusa, Tokyo, he has gained exceptional skills to pick just about any lock. Using his exceptional skills, Yataro then finds himself solving various mysterious cases, while also trying his luck with the girls.

• Hayato Ichihara
• Sei Ashina
• Gota Watabe
• Sousuke Takaoka
• Yoshiyuki Morishita