Watson's heart sank as he watched Toby going back and forth over this latest intersection. Not that he wasn't grateful for a moment's rest... still, it would be dark soon, and the temperature was already dropping rapidly. Dawson had explained about the aniseed pod that Basil had put under the cab wheel, which had led the hound a long way, but now it seemed that the trail had somehow become confused.
"Could they have doubled back?" Dawson asked.
"Perhaps... Ah, there, he's off again!"
Toby had made up his mind at last, turning into the wider street, but as they went on, Watson grew increasingly uneasy, finally realising what was troubling him. "Toby, Dawson, stop, we have to go back!"
"What is it?"
"We're following the wrong trail. Look where we are!" Watson pointed to where Toby had been recently sniffing: along the centre of the street. "The scent was on the left cab wheel, how could it suddenly switch to the right?"
"So unless they were driving on the wrong side..."
"Something else must have crossed their path and picked up the scent somehow! Come on, back to the corner!"
Casting around afresh at the crossroads, Toby soon dashed off in a new direction. Then Dawson gasped as a faint sound reached his ears: a frenzied snarling and barking...
"Basil!"