The duo dashed to the batmobile, throwing on seat belts and such as the engine started. Batman grabbed the wheel and slammed the pedal to the floor, and the vehicle shot into the long opening that lead to the road.
It was silent as the caped detective ran through their objectives again in his mind: somewhere in the city, the Joker and his henchmen were preparing for their biggest heist in months, and he and Robin had yet to discover just what the lunatic wanted with the giant shipment of children's toys swiped last week. This was serious. This-
Was that... singing?
Batman looked at the boy in the passenger seat as he mumbled a little tune. "Secret tunnel... Secret tunnel... Through the mountain... Secret secret secret secret tu-" Robin noticed Batman staring. "...What?" he asked, obviously unaware that his song had been audible, and now turning a bit red. "We're in a secret tunnel. ...Anyway... what do you think Joker is up to?"
Batman stared a bit longer, then turned his attention back outside the windshield as they came onto the road. "When we get home... I'm telling Alfred to stop letting you watch so much cartoons."
"Good luck," Robin muttered. "He watches them with me."
Back at the Batcave, Alfred sighed, looking at two rocks which had just fallen from the cave ceiling into his path back up the stairs. He inched around them, singing a melody as he did:
"Oh, don't let the cave-in get you down! Don't let the falling rocks turn your smile into a frown. When the tunnels are darkest... that's... when they'll chase the clown, hey! Don't let the cave-in get you down, Alfred!"