"So you're telling me," Watson said to the mouse riding in his palm as they hurried downstairs, "that you and, ah, Basil have been living under 221B all this time?"
"Mostly," the mouse shrugged, who had introduced himself to a still-bemused Watson as Dr. Dawson. "It's not as though we've been a nuisance, now, is it?"
"You'd have to ask Mrs. Hudson about that," Watson smiled, which faded again almost immediately. "You said Basil went after Holmes?"
Dawson nodded. "We couldn't wait for you to come to, so Basil hitched a ride on the cab, leaving Toby and I to follow with you."
"But how are we to find them?" Watson frowned, bundling himself into coat and hat and grabbing a spare overcoat for Holmes. "Surely even Toby can't track a single cab across London!"
"On the contrary," Dawson smiled smugly as Watson opened the front door. "Toby! Seek, boy!"
Toby dashed out the door and down the steps, nose to the cobbles, sniffing in all directions. The two doctors lost no time in joining him, Watson barely managing to fasten the hound's leash to his collar before he was off, tail in the air, whining eagerly. Caught off balance, Watson could only do his best to keep up, wishing far too late that he'd thought to bring his medical bag...