Mr. Graves walked among the guests, looking them over from head to toe. He asked each person if they stole the jewel. When nobody confessed, he demanded that everyone empty their pockets, but none of them had the diamond.

For the first time that night, Mr. Graves noticed that Tim was younger than the other kids. “You!” he shouted at Tim. “You’re not one of my son’s friends!”

“He’s with me, Mr. Graves,” Barbara said. “I didn’t think it would be a problem.”

“Ease up, Dad,” Jason said. “This is Barbara Gordon, the police commissioner’s daughter. She didn’t come here to rob you!”

Mr. Graves sighed. “You’re right,” he said. “Please accept my apology.”

“Of course,” Barbara replied. “If you let me, sir, I’ll help you find the diamond.”

“That’s kind of you, Barbara,” said Mr. Graves, “but everyone should just stay put. This thief could be dangerous.”

Barbara realized that Mr. Graves and the other guests didn’t know that she was actually Batgirl. Barbara had to find a way to help, without revealing her true identity. She stepped into an empty room and called the Dark Knight.

“Batman,” Barbara began. “There’s been some trouble at —”

After a sudden burst of static, the phone went dead. The steel doors that had secured the house were also blocking all cell phone signals. She and Tim would have to handle this situation on their own.

* * *

At Arkham Asylum, Batman hung up his phone and paced back and forth inside Catwoman’s cell. What was Barbara trying to tell me? he wondered. She sounded worried.

The Dark Knight had already gotten the janitor to confess. She admitted that the real Catwoman offered her one million dollars to unlock the cell. The deal turned out to be more than she had bargained for.

Batman spotted a shredded newspaper in a trash can. He picked up several torn sections of the front page.

As the Dark Knight placed each piece of paper on a table, the mystery came together like a puzzle. “$100 million,” read one of the pieces. “Black Cat Diamond,” read another.

Then Batman looked at the final piece. “Stephen Graves,” he said to himself.

Batman threw down the newspaper and raced out of the room. He had a costume party to crash.

* * *

Meanwhile at the Graves Mansion, Tim studied the other guests. Something about the crowd was bothering the teenage super hero. He silently counted the people standing in the room.

“Hey, one of the cats is missing!” Tim suddenly shouted.

“Of course, the Black Cat is missing, genius,” another teenager said. “Why do you think we’re locked in here?”

“What does he know?” said a boy in a Batman costume. “He’s only a sidekick!”

Several of the guests chuckled. They didn’t know Tim was the real Robin.

“You’re not listening!” shouted Tim. “There used to be four girls in Catwoman costumes. Now, there are only three.”

Mr. Graves looked around. “He’s right!” he said. “You don’t think —?”

“Look!” Tim exclaimed. He pointed toward a wooden banister, which led up a tall staircase. “Claw marks!”

“Wait here! I’m calling the police!” said Mr. Graves. “She’s probably still in the house somewhere.”

Tim had taken on Catwoman before. He knew that she would be long gone by the time the police arrived.

“We have to search the house before she can escape,” Tim said to Barbara and Jason as he ran ahead of them up the stairs.

“No!” Jason said. He grabbed Barbara by the arm to stop her from going up. “Stay behind me. I’ll protect you.”

Barbara allowed Jason to go in front of her. She could barely hide her smile. That’s cute, she thought. He thinks I need protecting. If he only knew . . .

At the top of the stairs, Barbara and Jason caught up to Tim. The floor had thirteen doors — six on the left side and six on the right. On the final door, at the end of the hall, glowed the number thirteen.

“Oh, great,” said Jason, looking down the creepy hallway. “I almost forgot about my dad’s Thirteen Doors of Terror!”

“Thirteen what?” asked Barbara.

“This is my dad’s famous haunted house,” replied Jason. “He’s rigged these rooms with some of the scariest special effects on Earth. It’ll be impossible to find Catwoman in here.”

Nearby, Tim crouched at the keyhole to the door closest to the stairs. He was trying to pick the lock.

“What are you doing, Tim?” Barbara said. “Didn’t you hear Jason? We need to figure out a plan.”

“Come on, Barbara,” said Tim. “I’m not scared of a few cardboard skeletons and some fake cobwebs. Follow me!”

Tim stood up and opened the door. He stepped inside the darkened room. Suddenly, a giant bat dropped down from the ceiling and soared toward his head.

“Ah!” Tim shouted. He quickly bolted out of the room. “What is that thing?!”

Jason reached up and plucked the bat out of the air. He threw the creature onto the ground, lifted his foot, and stomped down hard. The electronic bat exploded beneath his shoe.

“Sorry about that,” Jason said. “I told you that my dad likes to surprise people. He’s always adding things to his collection. I never know what I’ll find when I open a door in this house.”

“Thanks for the warning,” Tim said.

The Boy Wonder went through the next door, and Barbara and Jason followed. They searched each room on the floor, discovering robotic ghosts, mummies, werewolves, and other frightening props.

At the twelfth door, Tim paused for a moment. “Only two doors left,” he said. “She has to be here somewhere.” Then the secret super hero stepped inside.

Tim watched two hands slash across his chest. “Ha!” he laughed. “I know this is fake, but that felt pretty real.”

“Um, Tim,” said Barbara, pointing at his chest.

Tim looked down and saw claw marks on his Robin uniform. When he looked back up, Catwoman was standing right in front of him!