Now only the moon shone on the snow.

Jack looked around for the polar bear.

She was gone.

"Where'd she go?" asked Annie.

"I don't know," said Jack. He looked over thetundra. There was no sign of the giant bear or hercubs.

"Maybe she's not interested in scientific reasons,"Jack said.

Annie sighed. She took off her bear mask andhanded it to Jack. He put both their masks in his pack.

"Now what?" asked Annie.

They looked around. The vast fields of snow endedin darkness. Jack had no idea where they were.

He shrugged. "I guess we just have to walk andhope for the best.""Wait--listen," said Annie.

From the distance came howling sounds. They grewlouder and louder.

"Yay! We don't have to wait long!" said Annie. "Thehuskies are coming!"Howling filled the night as the dogsled came intoview.

The seal hunter was running beside it.

"We're here! Over here!" called Jack. He ran towardthe sled. Annie followed.

"I was afraid you were lost," said the seal hunter.

"We were!" said Annie. "And we got stuck on thinice, too! But a polar bear helped us.""Yeah," said Jack. "And we wore your masks andthey made us feel like bears--""Yeah, the masks made us brave," said Annie. Shecaught her breath.

"Oh, man, wait--" said Jack. Annie's words soundedfamiliar.

He took out his notebook and read Morgan's riddlealoud:

I cover what's real and hide what's true. Butsometimes I bring out the courage in you. What am I?

"A mask!" Jack and Annie said together. The sealhunter smiled.

"You knew!" said Annie.

"It was for you to discover," said the seal hunter.

"Not me."Jack pulled the bear masks out of his back-pack.

"Here," he said. "Thanks a lot."The hunter took the masks and put them inside hisparka.

"We can go home now," said Jack.

"Do you mind taking us back to the tree house?"said Annie.

The seal hunter shook his head. "Climb on," he said.

Jack and Annie climbed onto the dogsled. "Mush!"said the seal hunter.

"Mush!" said Annie.

"Mush!" said Jack.

Snow began to fall as they took off across the darkice.