Chronoclock Drama CD is a short story featuring Cro. While lounging around the Sawatari household she enlists D.D. to find out more about the girls that are close to Rei and their relationship to him. Naturally curious about humans, Cro reasons that whoever Rei gets together with will be someone that will also end up being in contact with Cro as well. Leave it to Detective D.D. to get the scoop!