Back at the Graves Mansion, Barbara and Tim had rejoined the rest of the guests. Mr. Graves was leading them on a tour through the first floor of his mansion.

“Each room of my house is built around historical Halloween objects,” continued Mr. Graves. “This room contains my frightening collection of masks. Only the brave of heart should enter here.”

Mr. Graves invited them into the room. Dozens of creepy masks decorated the walls. Some were hundreds of years old.

“Scary, aren’t they?” said their strange host. “Originally, Halloween masks were worn to frighten away ghosts, not people. My, how times have changed.”

In the back of the group, one of the guests raised his hand. “I thought this party was going to have a haunted house?” asked the teen. “This stuff is boring.”

“Yeah, Dad,” said Jason, sensing his friends were about to leave. “Nobody cares about these silly antiques.”

“Oh, really?” replied Mr. Graves. He opened the door to the next room. “Let me show you one last item. It’s my favorite, and most valuable, treasure in the house.”

Except for a glass display case, the room was completely empty. Inside, sat a sculpture of a sparkling black cat.

“People all over the world have feared black cats for hundreds of years,” said Mr. Graves, standing near the sculpture. “Many people believe that they bring bad luck.”

Mr. Graves typed a secret code into the electronic keypad near the display case. “But that’s not true,” he continued. “This black cat was cut from a rare diamond. And tomorrow, it will bring me nothing but good fortune!”

The display door swung open. Mr. Graves took out the sculpture and held it in the air. “I’m selling this Black Cat Diamond to a private investor for $100 million,” he exclaimed.

The guests gasped in amazement.

“Not so silly, huh, Jason?” he said.

* * *

Back at the asylum, Batman entered Catwoman’s cell. He kneeled next to the villain and removed a lock-picking device from his Utility Belt. He carefully inserted the device into the shackles and turned it.

As the cuffs released from the prisoner’s wrists, Batman jumped to his feet. He expected Catwoman to attack with her razor claws. But instead, she stood, walked toward Batman, and gave him a hug.

With her hands free, the woman in the black outfit removed her mask. Instead of Selina Kyle, Catwoman’s true identity, Batman saw the face of another woman — a janitor at Arkham Asylum.

“But, but, how —?!” said a prison guard.

“Never underestimate Catwoman,” said Batman. “She can escape any situation.”

At the costume party, Mr. Graves held the Black Cat Diamond toward his guests. “Take a good look,” he said. “You may never see this priceless jewel again —”

Suddenly, the lights went out again!

People screamed and ran in all directions. Tim pushed through the crowd of guests and found the light switch. He quickly turned them back on.

Everyone was nervous, even Mr. Graves. The host looked down at his hand. “It’s gone!” he screamed. “Someone has stolen my Black Cat Diamond!”

The guests stood in shocked silence as Mr. Graves paced the room wildly.

“Come on, Dad,” Jason said. “You’ve had your fun. Put the diamond back in its display, and let’s move on.”

Mr. Graves looked at his son. His face went pale. “This isn’t a joke,” he said. “The diamond has been stolen. Someone in this room is a thief!”

Mr. Graves walked over to a wall unit that controlled the security system for the entire house. He pressed a red button on the control panel. In an instant, heavy steel doors came down over all the windows and exits. The house was now completely sealed.

“Until I find the Black Cat Diamond,” shouted Mr. Graves, “nobody gets in or out of this house!”