"Poor Pee Bee!" said Peggy. "Now he's going crazy on us!"
Pee Bee ran back and forth at one edge of the meadow, helplessly wringing his hands but not daring to approach his friends.
"Look at this," said Martia. "It's a cairn!"
They had not noticed it before, because it was small and half concealed by weeds.
"Who could have put that there?" asked Peggy.
"Perhaps one of our captured friends," said Uncle Andy, squatting down to examine it.
"Get off'n dat ground!" shouted Pee Bee, at the top of his voice.
Uncle Andy removed the top rock from the cairn and uncovered a metal pipe with a screw cap on it. "Oh, oh!" he said. "Booby trap!"
"Unscrew it!" Henry urged him.