"Well, if you know so much, tell us where it is then!" snapped Jerry
Muskrat.

"In the Laughing Brook, of course," replied Grandfather Frog.

"No such thing!" said Billy Mink. "I've been all the way down the
Laughing Brook to the Big River, and I didn't find a thing."

"Have you been all the way up the Laughing Brook to the place it
starts from?" asked Grandfather Frog.

"No-o," replied Billy Mink.

"Well, that's where the cause of all the trouble is," said
Grandfather Frog, just as if he knew all about it. "It's the water
that comes down the Laughing Brook that makes the Smiling Pool, and
the Smiling Pool never could dry up if the Laughing Brook didn't
first stop running."

"That's so! I never had thought of that," cried Little Joe Otter.
"I tell you what, Billy Mink and I will go way up the Laughing Brook
and see what we can find."

"Chugarum! Let us all go," said Grandfather Frog.

Then the five put their heads together and decided that they would
go up the Laughing Brook to hunt for the trouble.