It was much easier walking down 1,652 steps than walking up. Jack and Annie walked down and down and down and down and down and down and down and down and down and down and down—until finally they stepped onto the ground.

Jack noticed that the two-seater bicycle was gone. “I guess those two people came and got their bike,” he said.

Jack and Annie looked around. Exhibits were covered and gates were locked. All the motion and noise of the World’s Fair had ended for the day. The living encyclopedia had gone to sleep. Suddenly Jack felt very exhausted.

“Home?” said Annie.

Jack nodded. “Frog Creek,” he said, sighing.

Jack and Annie hurried over the bridge and across the avenue. “Those guys were really nice,” said Jack as they walked through the dark, rose-scented park.

“I know,” said Annie. “They acted like regular people. But they’ve done all those amazing things.”

“Yeah,” said Jack. “They’re like magicians in disguise.”

Jack and Annie came to the magic tree house. They climbed up the rope ladder and looked one last time out the window. The Eiffel Tower seemed to stand watch over Paris, its spotlights sweeping over the city.

Jack pulled Merlin’s letter out of his satchel. He opened it and pointed to the words Frog Creek. “I wish we could go—”

Before Jack could finish making the wish, he and Annie were bathed in brilliant white light. Jack looked up. One of the beams of the tower’s spotlights had come to rest on the tree house. It shined on them for a long moment.

With both hands, Annie waved wildly into the blinding light. Jack waved, too.

“Good night, magicians!” Annie shouted.

Jack laughed. Then he pointed at Merlin’s letter again and finished his wish: “… home to Frog Creek,” he said.

The wind started to blow.

The tree house started to spin.

It spun faster and faster.

Then everything was still.

Absolutely still.

Jack opened his eyes. He and Annie were dressed in their regular clothes again. Dusky light filtered into the tree house. No time at all had passed in Frog Creek.

“That was a great trip,” Jack said softly.

“Really great,” said Annie.

Jack pulled the guide book to the 1889 Paris World’s Fair out of his backpack. He left it on the tree house floor along with Merlin’s letter. But he kept Teddy and Kathleen’s book of magic rhymes.

“So. We have three rhymes left for our fourth adventure,” he said.

“Quack, quack,” said Annie.

“Very funny,” said Jack. “Ready?”

“Yep,” said Annie. She climbed down the rope ladder, and Jack followed.

As they started walking through the darkening woods, the world felt familiar and ordinary again. “I can’t believe we just met all those guys,” said Jack. “I can’t believe I actually shook hands with Thomas Edison.”

“You mean with Alva,” said Annie.

“Yeah. Alva…. Wow,” Jack said softly.

“What do you think Merlin meant when he said that we had lived all their secrets, as well as learned them?” said Annie.

“Well, think about it,” said Jack. “We wouldn’t have gone on our mission in the first place if we didn’t have a love for adventure and responsibility—like Mr. Eiffel.”

“Right,” said Annie. “And we sure put a lot of sweat into our mission—when we climbed the stairs.”

“And we didn’t lose hope when the door of the institute was locked,” said Jack. “We stuck around until another door opened.”

“And you prepared us by reading from the research book,” said Annie, “so chance favored us when we heard someone call Thomas Edison ‘the Wizard of Menlo Park.’”

“And chance favored us when those two people lent us their bike,” said Jack.

“Actually, I don’t think that was chance,” Annie said.

“What do you mean?” said Jack.

“Did you notice that man looked more like a kid in disguise?” said Annie. “His beard and mustache looked kind of fakey.”

“I did notice that!” said Jack. “But there was so much going on, I didn’t have time to think about it.”

“And the woman talked in that funny, squeaky voice, and the veil of her hat covered her face,” said Annie. “And the guy told us to spin like a whirlwind. That was a weird thing to say, but it reminded us of the rhyme in Teddy and Kathleen’s book.”

Jack nodded slowly. Then he smiled. “You think those two were actually Teddy and Kathleen?” he said.

“Maybe,” said Annie. “On our last three missions, I felt like they were with us, helping us get to the right place at the right time.”

“Next time, maybe we can catch them when they help us,” said Jack.

Annie laughed. “Yeah, we’ll try to surprise them for a change!”

“Good plan,” said Jack.

A bell jingled in the distance.

“Ice cream!” said Annie.

“Yep, that’s our mission now!” said Jack.

The ice cream bell jingled again. Jack and Annie ran out of the woods into the soft summer twilight.