Henry could hardly believe that Nora had outsmarted them.
She had led them into the neighbors' yard and then disappeared.
But he wasn't ready to give up yet.
"I have an idea," he told Maggie, Cole, and Nathan.
"Nora probably waited for us to start looking for her.
Then she sneaked back through the hedges.
If we hurry, we might be able to find her before she makes it to the house."
Nathan nodded. "Let's go," he said.
He led The Lemonade Detectives through the hedge into his own yard.
They got there just in time to see Nora racing toward the house.
"Stop right there!" Nathan yelled loudly. "We caught you, Nora!"
They ran toward her.
Just then the back door flew open and Nora's parents rushed out.
"Oh no!" Nora's mom exclaimed. "She got out again!"
Nora's dad looked worried. "Hush, don't wake her," he told his wife.
"Someone told me you're never supposed to wake a sleepwalker."
"She's not really sleepwalking, Dad!" Nathan said.
Henry had been watching Nora.
As soon as she'd seen her parents, she'd closed her eyes and held out both arms in front of her.
Henry thought she looked more like a zombie than a sleepwalker.
But her act seemed to be fooling her parents.
"That's not a nice thing to say, son," Nathan's father scolded.
"Your sister could get hurt if she keeps sleepwalking like this.
I wonder how she got outside this time."
"She climbed out her bedroom window," Nathan said.
"That's enough, Nathan," his father said. "This is no time for jokes."
"Come with me, sweetie," Nora's mother said softly as she started guiding Nora toward the house.
"Let's get you safely back to bed."
"It's time for you to come inside too," Nathan's father told Nathan.
Then he glanced at Henry, Maggie, and Cole.
"And you kids had better head home. It's getting late."
"Late? It's not even eight o'clock yet," Maggie said.
Henry grabbed his cousin by the arm and pulled her toward the front of the house.
"Yes, we'd better go," he told Nathan's dad politely.
"See you tomorrow, Nathan."
Now that Nora had been caught "sleepwalking" again, Henry guessed that her parents would watch her very closely.
She probably wouldn't be able to sneak out again that night.
That meant any more detective work would have to wait until the next day.
The following morning Henry was eating breakfast when Maggie hurried in through the kitchen door.
"Good morning, Maggie," said Henry's mother, who was also Maggie's aunt.
"Would you like some scrambled eggs?"
"No thanks, Aunt Susan. I already ate."
Maggie sat down at the table across from her cousin.
"Hurry up, Henry," she said.
"I want to go back to Nora and Nathan's house and investigate."
"Okay," Henry said. "Let's call Cole and tell him to meet us there."
Nathan was waiting in front of his house when the three detectives got there.
"What's the plan for today?" he asked.
"Do you have any theories about what Nora is doing when she sneaks out?"
"Not yet," Henry admitted. "But at least we know she's not sleepwalking."
Cole nodded. "She was wide-awake when she ran away from us, that's for sure."
"I still think she was heading for the tree house when she heard us," Maggie said.
"Maybe we should search for clues up there."
Nathan seemed doubtful. "Why would she sneak around just to go to my tree house?" he asked.
"She's allowed to climb up there whenever she wants, as long as she tells someone where she's going."
"Really?" Cole said. "My friend Bruce never lets his little sisters in his tree house."
"Nathan must be much nicer than your friend Bruce," Maggie said with a laugh.
"Anyway, I still think we should look in the tree house."
"You're right, Maggie," Henry agreed.
"It's worth checking out, just in case."
All four of them hurried past the house to the backyard.
Then they climbed up the ladder leading into Nathan's tree house.
"Wow," Cole said, looking around.
"This place is really cool, Nathan!
You can see half the neighborhood from up here."
Henry wasn't very interested in the view.
He was busy looking around for anything suspicious.
But all he saw were some empty candy wrappers and Nathan's favorite comic books.
There was no sign that Nora had been in the tree house recently.
"Oh well," Henry said. "I guess this idea isn't working.
Maybe we'll have to wait until tonight to try another stakeout."
"Okay," Maggie said, and Nathan nodded.
Cole wasn't listening. He was still looking out the window.
"Hey, check it out!" he said.
"Nora just climbed out the playroom window again and is sneaking across the yard!"