Sirius raised his eyebrows. "There aren't a lot of dogs trotting around the Ministry, and sniffing out anything on stone floors in an environment with that many people is difficult enough if you know what you're looking for, which we don't."
He shrugged. "If we want to try it, though, the best plan would probably be for me to go in with a Ministry employee -- Tybalt, for example -- who can drape your invisibility cloak over me, as needed."