human
There's some reason why this spot should be different from the rest, he said, after having verified his discovery.
gpt
It's all open to the weather, like every other part of the alley, and there's only one explanation. There's heat coming up from beneath. That means that there must be an open space beneath this spot. I wish I dared use my flashlight.
human
Wait a minute, said Bart.
gpt
I'll slip out to the mouth of the alley and see if the coast is clear. If it is, I'll give a low whistle and then you flash your light and see what it shows you.