The kids began talking all at once.

  “… ghosts … porch gears … experiment … keyhole switch … portrait … Herbert? … BOO! … architecture … gargoyle … library … booger … blueprints …”

  Aunt Bernice laughed and raised her hand.

  “One at a time,” she said.

  Rosie jumped in.

  “Yesterday, I saw gears under the porch boards,” she said. “So I figured the moving porch wasn’t a ghost. It was just a gizmo! The porch went crazy when we put the wrong key in the lock. When we moved the crooked portrait, the house started making sounds. I figured out those were switches. Herbert Sherbert was a great engineer, and he rigged the house to act like it was haunted.”

  “Like a booby trap?” asked Miss Weatherbee. “Why would he do that?”

  “His heart broke when his family died,” said Ada. “Maybe he didn’t want strangers living in the house, so he scared away people who tried to get in.”

  “Like you said, Miss Weatherbee,” said Iggy, “ghosts are bad for house sales. If that was Herbert Sherbert’s plan, it worked! It kept people from trying to buy the house.”

  Miss Weatherbee nodded.

  “How did you kids get in today?” asked Aunt Bernice. “Bee and Beau boarded up the window yesterday.”

  “I invented a gadget,” said Rosie. “It’s the Keypopper 7!”

  She held up a contraption with a bunch of weird spikes sticking out of it.

  “This part opens the door,” said Rosie. “This part trips the booby traps! You can keep it for when you live here.”

  “You are all so clever,” said Aunt Bernice. “But I have to sell the place.”

  “What about the antiques?” asked Ada.

  “Oh, my dear,” said Aunt Bernice. “We can’t even guess what was here so long ago.”

  “But we can!” said Sofia. “Just look!”

  She pulled the library book from her satchel and flipped through the pages.

  “Here!” she said.

  Sofia held up a photograph of Mrs. Candace Sherbert and another woman standing in the Great Hall of the mansion—and the hall was full of expensive-looking furniture and antiques! Sofia read the photograph’s caption. “January 12, 1916. Candace Sherbert hosted Ida B. Wells in the Great Hall. Ida B. Wells is a leader in the fight for women’s suffrage in America. Suffragists, like Candace Sherbert and Ida B. Wells, believe that women should have the right to vote. ‘Ice cream for kids,’ said Mrs. Sherbert. ‘Votes for women!’”

  “That is history!” said Aunt Bernice. “And look at all that furniture! But it’s all gone now. We’ve searched everywhere.”

  “There’s one place we didn’t look!” said Iggy.

  He took out his sketch of the mansion roof.

  “This is what we saw from the cheese-copter,” he said.

  “There must be a hidden room!” said Ada. “Maybe this key from the lawyers opens the door to the secret space!”

  She held up the ribbon with the key.

  “But where is this room?” asked Aunt Bernice.

  Iggy held up his drawing.

  “Here!” he said.

  CHAPTER 19

  Iggy’s hand-drawn blueprint showed the rooms they had visited. He pointed to a blank area in the middle of the second floor.

  “Architects don’t leave blank parts in a house,” he said. “It has to be a secret room!”

  They followed the blueprint to a second-floor hallway with many bedroom doorways to the right, but no doors to the left.

  “The bedrooms on the right have windows to the yard,” said Ada. “So, the secret room has to be on the left wall.”

  “But where?” asked Sofia.

  There were eight panels along the hallway. The panels were covered with complicated Art Nouveau wallpaper with hundreds of flowers and ice cream cones.

  “That’s a lot of ice cream cones,” said Miss Weatherbee.

  The kids spread out and searched for a keyhole, a switch, or a button. Anything that would open a hidden door. They found nothing.

  Sofia sat down and looked at the library book.

  “Let’s face it,” said Aunt Bernice. “The furniture is long gone.”

  “Do you think the caretaker took it?” asked Ada.

  “Oh, no,” said Aunt Bernice. “Monsieur Glace was a kind old man. He lived in the little cottage and gave candy to everyone he met.”

  “I remember him!” said Iggy’s father. “He had a little beard and a green cap and he always looked exactly the same.”

  “He did! I don’t think he ever changed,” said Aunt Bernice. “And he always said the same thing …”

  “‘Happiness is the key to everything!’” said Aunt Bernice and Iggy’s father at the same time.

  They laughed.

  “Why did he always look the same?” asked Ada.

  “I don’t know,” said Iggy’s dad. “He just always did.”

  Just then, Sofia popped up and ran to the others.

  “Aha!” she cried. “Look at this one!”

  She showed them another article.

  October 7, 1918

  It is a sad day in Blue River Creek.

  Our most famous citizen, Herbert Sherbert, creator of Green Goose ice cream, bids farewell to our fair city. Following the tragic loss of his beloved wife, Candace, and his daughter, Honey, he is returning to France. He leaves behind a grateful town and many happy customers.

  His seventy-year-old cousin, Pierre Glace, will act as caretaker to the Sherbert House and estate. He will arrive tomorrow on the three o’clock train.

  The group studied the photo.

  “Why would he have such a small suitcase for such a long trip?” asked Miss Weatherbee.

  “Why would he go to France in 1918?” asked Agnes Lu. “The First World War was going on! That would be dangerous!”

  “Why did Pierre Glace arrive after Herbert left?” asked Iggy’s mother. “Wouldn’t he want to see his cousin?”

  “Doesn’t glace mean ‘ice cream’ in French?” asked Aunt Bernice.

  “How could Pierre Glace be seventy when he got here in 1918 and still be alive fifty years later? And look the same?” asked Iggy’s father.

  “Look at us!” said Aunt Bernice. “We’re all becoming Questioneers!”

  Everyone laughed.

  Everyone but Iggy.

  Iggy looked sadly at the picture for a moment. Then he asked a simple question.

  “Where is his cat?” he asked.

  CHAPTER 20

  “I’d never leave Bricks if I moved to France,” said Iggy.

  Rosie looked worried.

  “What if—” she started.

  Iggy knew what she was going to say. He thought about the cat statues near the old cottage. Were they statues? Or were they gravestones?

  He tried to remember the words on the statues. What were they? Whimsy and Wonder and—

  His thoughts were interrupted by Agnes Lu.

  “Bernice,” she said. “Herbert Sherbert wanted someone like you to have his house. Wouldn’t he leave a clue about the secret room?”

  Whimsy and Wonder and what was it?

  “I am confused about everything,” said Miss Weatherbee.

  As the word everything left her mouth, a different word entered Iggy’s brain.

  HAPPINESS!

  “Happiness!” he yelled. “Whimsy and Wonder and Happiness!”

  The group looked at him oddly.

  “Happiness!” he said jumping up and down. “The key to EVERYTHING is HAPPINESS!”

  “What?” asked Ada.

  “Herbert Sherbert left a clue!” said Iggy.

  “Where?” asked Aunt Bernice.

  “EVERYWHERE!” said Iggy. “Don’t you see? Happiness is the key to everything.”

  “We know,” said Rosie. “That’s his slogan.”

  “No,” said Iggy. “Happiness was his cat! Its grave is by the cottage.”

  “Oh my,” said Aunt Bernice. “Herbert Sherbert put that message on buildings all around town! In the original library and the train station!”

  “The important buildings where everybody would see it,” said Iggy. “And as part of the architecture.”

  “And his cousin said that to everyone!” said Ada.

  “Wait a minute!” said Sofia. “What if he wasn’t?”

  “Wasn’t what?” asked Ada.

  “What if Pierre Glace wasn’t Herbert Sherbert’s cousin?” Sofia said. “What if he was Herbert Sherbert?

  “Think about it!” she continued. “What if Herbert Sherbert took a train from Blue River Creek one day and came back the next day in a disguise? He pretended not to speak much English so people wouldn’t hear his voice.”

  “Except when he passed along the clue,” said Iggy’s father.

  “Why did he hide the furniture?” asked Ada.

  “To keep away thieves,” said Miss Weatherbee. “A house full of expensive furniture and art from around the world would be quite a prize for thieves.”

  Aunt Bernice put her hand to her mouth.

  “Poor lonely soul,” she said. “He scared everyone away to protect the memory of his family. I can imagine him sitting in that chair by the portrait all alone.”

  “I don’t think he was alone,” said Iggy. “I think he had a cat.”

  CHAPTER 21

  “I saw three cat statues by the cottage,” Iggy said. “Happiness wasn’t the only one. So maybe he always had cats.”

  “If his cat was Happiness,” said Ada, “what did the clue mean?”

  They stepped into the Thailand room and looked at the mural. The white cat stared back at them.

  Iggy stared at the cat’s odd eyes. What was it trying to tell them?

  The green gemstones on the cat’s painted collar seemed to sparkle in the afternoon light.

  Sofia looked closer at the collar.

  “That’s so beautiful,” she said. “The green gems are sitting on tiny ice cream cones. Maybe one of the green ice cream cones in the house is a switch, too!”

  Aunt Bernice groaned.

  “That’s no help at all,” she said. “There are a thousand little green ice cream cones on the walls and floors and ceilings of this house. We could spend years testing them all.”

  They walked back to the hall.

  Iggy looked at his blueprint and at the hallway lined with panels.

  “It has to be here somewhere,” he said.

  Iggy looked around. He frowned. He thought. Then he thought some more.

  “What did Clerk Clark say about the building permits?” he asked.

  “She said the last updates on the house were done here in 1918,” said Sofia.

  “A few months before Candace and Honey Sherbert died,” said Ada.

  “Someone did work after that!” Iggy said. “Look!”

  Iggy pointed to the panel of wallpaper behind Aunt Bernice.

  “It’s ice cream, Iggy,” she said. “Just like the other panels.”

  “No!” said Iggy. “It’s different.”

  The pattern was complicated and filled with colored ice cream cones like the other panels. But it had sharp angles instead of winding curves. It was sleek and modern.

  “It’s Art Deco!” said Iggy’s father.

  “Good gracious, Ignatius,” said his mother. “It is!”

  “So?” asked Sofia.

  “So,” said Iggy’s mom, “Art Deco was introduced to the world in 1925 in Paris. It wouldn’t be on wallpaper before then.”

  “So?” asked Rosie.

  “So,” said Iggy, “this panel is newer than the others. Somebody put this wallpaper up after 1925! The door has to be behind this one!”

  “Is there a green ice cream cone?” asked Ada. “Like on the cat’s collar?”

  The tiny ice cream cones covered the panel. There was chocolate, strawberry, vanilla, lemon, orange, and green ones. They were covered with multicolored sprinkles.

  “They’re everywhere,” said Iggy. “It’s not the ans—”

  “Wait!” yelled Sofia. “Look at that cone!”

  She pointed to a vanilla cone near the top. It was different from the others.

  Instead of white ice cream with green sprinkles, the cone contained one beautiful white Art Deco cat with a green-jeweled collar.

  “That’s it!” said Iggy. “That’s got to be it!”

  Ada handed the key to Aunt Bernice, who pushed it through the green spot on the cat’s collar with a SNAP!

  “It’s a keyhole!” said Aunt Bernice.

  She turned the key.

  SNAP! CLICK!

  The panel swung open.

  “Zowie!” said Ada.

  “You can say that again,” said Aunt Bernice.

  “Zowie,” said the Questioneers.

  CHAPTER 22

  The room was filled from floor to glass ceiling with stacks of chairs, tables, bedframes, mirrors, paintings, dishes, and statues. Everything needed to furnish a mansion. In one corner stood a strange, brightly painted organ with long copper pipes. It was Herbert Sherbert’s original ice cream cart. The invention that started it all.

  An iron and glass ceiling arched over the entire space. Only a few panes of glass were missing in the ceiling. A stack of wooden crates beneath one of the missing panes showed signs of water damage.

  They looked around in awe.

  “Look, Aunt Bernice!” said Ada.

  A handwritten note sat on a small table.

  Welcome, My Friend,

  At last, you are here. Did you have help? We all have help, if we are lucky. I was a very lucky man, indeed. My life was full of love.

  When my loves left, I shut out the world. I did not want it here, melting away my memories like ice cream in the sun. Perhaps I was foolish. Time does not stop because we wish it to.

  I do not know when you arrived, but if you have found this note, the time is right for the house to find a new life. Once, this house echoed with laughter and joy. I hope that it will do so again for you. Though it has been silent for so many years, the love that dwelled within these walls still remains.

  Never forget: Happiness is the key to everything!

  Welcome home.

  Herbert “Pierre Glace” Sherbert

  CHAPTER 23

  Aunt Bernice wiped a tear from her eye.

  “I had so much help,” she said, looking at Iggy, Ada, Rosie, and Sofia.

  “And I have an idea,” she said. “I know how to fill this place with laughter again, just like Herbert Sherbert wanted.”

  “So, you’re keeping the mansion?” asked Miss Weatherbee.

  Aunt Bernice nodded.

  “I don’t blame you,” said Miss Weatherbee. “It’s almost as great as ten perfectly square apartment buildings. And I’m glad there aren’t any ghosts!”

  Suddenly, a deep rumble rose from the organ. A loud note erupted from the pipe. Then another note, and another. The keys of the organ popped up and down all by themselves.

  Miss Weatherbee jumped a foot off the floor.

  “Eeek!” she cried.

  Aunt Bernice and Iggy’s parents scowled.

  “Iggy?” said his father, tapping his toe on the ground.

  “It’s not me!” said Iggy.

  “We’re not doing it!” said Ada and Rosie.

  “Then who is?” asked Aunt Bernice.

  “It’s the ghost!” said Miss Weatherbee. “Enjoy your mansion, Mrs. Twist. Goodbye!”

  Miss Weatherbee ran from the room, down the stairs, and out the front door of the Mysterious Mansion. A moment later, the Questioneers heard the squealing of tires on the driveway as she sped away.

  They looked at one another with wide eyes.

  The organ played faster and louder. Then, suddenly, it stopped. There was silence. Then, something rattled behind the organ. Iggy gulped and took a step toward it.

  Iggy stepped closer.

  And closer.

  And—

  He dived behind the organ.

  CRASH!

  SMASH!

  YEOOOOWWWWWW!

  A bloodcurdling yowl filled the air, like the sound of a woman’s scream.

  The group gasped. Then suddenly, out stepped Iggy Peck holding a white cat with two different-colored eyes. Iggy was followed by a parade of kittens.

  “Meet the Ghost Cat!” said Iggy. “And family.”

  “She must climb in and out of that missing windowpane up there,” said Rosie.

  “I’ll have to fix that glass,” said Aunt Bernice. “And get a new roof. And new wiring. And fix the kitchen window, and …”

  This time, Aunt Bernice smiled as she listed off the repairs the Mysterious Mansion needed.

  “And,” she said, “I’ll have to buy cat food, too! I wonder what a Ghost Cat and her kittens eat.”

  CHAPTER 24

  Iggy Peck stood next to Aunt Bernice on the porch of the Mysterious Mansion. A few weeks before, the house had been empty. Now, all of Blue River Creek was there, picnicking on the lawn. The sounds of music and laughter filled the air.

  Iggy looked into the Great Hall at the picnic mural of Honey Sherbert’s birthday party. He looked back at the yard. It was as if history had repeated itself.

  Iggy smiled at Aunt Bernice.

  “I think Herbert and Candace Sherbert would have liked this,” said Iggy.

  “Me too,” said Aunt Bernice.

  She nodded toward the portrait of Herbert and Candace Sherbert.

  Iggy blinked and looked again. The portrait looked different. Something small but important had changed, but what was it? Herbert stood next to his bride, Candace, with her bouquet of jasmine and her white cat.

  Iggy stared for a moment, trying to figure out what had changed. At last he knew. It was their eyes.

  The sorrow in their eyes was gone. It was replaced by joy.

  “How—?” Iggy started.

  “I don’t know,” said Aunt Bernice.

  Just then, Ada, Rosie, and Sofia ran into the Great Hall. They hugged Aunt Bernice and laughed.

  “Welcome home!” they said.

  “Thank you,” Aunt Bernice said, hugging them back. “Thank you all.”

  The Questioneers ran out of the house and joined the dance party on the lawn. The McCallister Sisters were starting a set of favorite tunes.