"I know my brother just told us to check," Luna said, "and Mrs. Belinda wasn't really a great host, but I hope it won't end so absurdly. I want to solve the case."

She was complaining on our way back from the old lady's house. We walked side by side, following an empty road.

"Calm down," I said. "First, let me ask you: how do you think someone could open that safe? How could they find the combination and bypass the fingerprint scanner?"

"Um... I'm not sure, but I think I saw this in a movie," Luna replied. "You can get fingerprints from common things like a door handle, using some sort of white powder and tape. My brother must know more about it."

"Yeah," I said, "but I was talking about when the owner of the fingerprints and the safe were in the same room."

Luna stopped and looked at me.

"Do you mean..." Her voice trailed off.

"Yeah," I said, looking at my own hand. "There's a simpler way. You just need to use the owner's hand itself."

"But how?" Luna asked. "Without waking her up..."

"Sleeping pill, I guess," I said.

"I see!" Luna exclaimed. "Then the culprit was either the maid or the chef."

I smiled. "Why?"

"Because it's suspicious for the gardener to get close to Mrs. Belinda's drinks or food, right?" Luna said. "On the other hand, the chef was the one who made it, while the maid most likely was the one who brought it to her. They had a lot of chances."

"Yeah," I said.

"Oh!" Luna seems to be on a roll. She has another idea. "The maid doesn't seem too strong," Luna said, "while Mrs. Belinda isn't exactly thin either. Can she even lift her to bring her to the safe?"

"That might not be necessary," I said. "Plenty of people store their safe right beside their bed."

"That's true," Luna said. "Wait, if Mrs. Belinda was sleeping because of a sleeping pill, why would she wake up then?"

"She said nobody knows the combination, right?" I said. "Then how did the culprit find out?"

"Um... checking her notes or something?" Luna said. "She might have written it somewhere."

"She said she memorized it," I said.

"Oh right," Luna said. "Then... probably they were just guessing? Something like her birthday or something?"

"What if it fails?" I asked.

"I don't know!" Luna said, frustrated. "What are you trying to say, anyway?"

"There's one last choice you can pick if everything else fails," I said. "Brute force. In other words, try all combinations from 0 to 9999."

"That's crazy!" Luna said. "How many hours do you think you need to do that?"

"That's exactly why," I said. "It would take so long that the sleeping pill's effect would already have worn off when the safe was successfully opened. When the old lady heard the sound of the opened safe, she immediately woke up."

"But... can the culprit be that patient?" Luna asked. "I just can't imagine myself spending hours entering all these combinations."

"If it's for a huge amount of fortune, why not?" I said. "Have you heard about prisoners who made holes using spoons for years?"

"That was real?" Luna said, in disbelief.

"Don't underestimate human resilience," I said. "Plenty of people are capable of doing something crazy."

"Fine," Luna said. "But then, who is the culprit? If you figured out this much, you must know, right? Is it the chef?"

"No," I said.

"The maid? Bela?" Luna said.

"Yeah," I said. "When I touched the cup, I saw a memory of the maid putting something into Mrs. Belinda's drink. Most likely a sleeping pill."

Luna stopped walking. "So that's why you suddenly said our job was finished," she said.

I nodded.

Luna suddenly fell silent, prompting me to ask, "What's wrong?"

"It's just... hard to believe," Luna replied. "I mean, she was nice to us. To think she's actually the culprit."

"Well, some people wear masks," I said. "We can't judge someone solely based on first impressions. Plenty of people hide their ugly side by acting nice."

Luna sighed. "I know," she said. "I know that, but sometimes I forget how ugly humans can be."

"Yeah," I said, "but you can complain about humanity later. We have more urgent things to do." 

"Huh?" Luna blinked, clearly confused. "What do you mean?"

"Don't you find this case from your brother weird?" I asked. "He told us to investigate without supervision. I mean, really?"

"What?" Luna said, looking even more perplexed.

"If two high schoolers tag along with real police, that might still be acceptable," I explained. "But letting us go alone? No wonder Mrs. Belinda was angry. Even if you're super nice, I'm sure you would be upset if your report was being handled by high schoolers. Anyone would think the police didn't take this case seriously."

"I see," Luna said, beginning to understand. "But so what?"

"You said it yourself," I replied. "Unlike how he appears on the surface, Atlas actually cares about helping people. So no matter how stupid the case may seem, isn't it weird for Atlas to let us handle it by ourselves? He's a good cop, right? There's no way he did it just because he was too lazy or busy."

"You're right!" Luna exclaimed. "This doesn't sound like my brother at all. Not to mention, he was always against me getting involved in cases before. Why the sudden change of heart? There must be a reason."

"Yeah," I nodded. "From the beginning, Atlas knew that this was either nothing or a failed attempt at stealing."

We continued walking, and I said, "If it turns out to be nothing, then there's no problem. But if it was a failed attempt at stealing, then a problem arises."

"Why?" Luna asked.

"If the police handle it," I explained, "the culprit might change her mind. Even if we know the maid was the culprit, we don't have any proof. Without anything missing, we can't catch her."

"I see!" Luna said, beginning to understand. "So my brother is trying to make the culprit believe that the police don't care about this case?"

"Exactly," I confirmed. "Thanks to that, she will make another move. Now that she knows the combination, she won't need hours to open it this time."

Luna nodded, looking nervous. "That makes sense. But won't she do it now then...? Aren't we too late?"

"I'm sure she wants to hurry up and do it," I replied. "But I doubt she will do it right now. She's patient, as we can see from how she figured out the combination. She won't risk it by acting hastily. She will wait until nightfall."

As we were walking, someone wearing a beanie hat approached us, but I didn't really pay much attention to him.

"Still," I said, "it's better to tell your brother as soon as possible, so he can prepare for the worst-case scenario."

"So that's why you're in a hurry," Luna said, beginning to understand.

"Yeah, and I don't really want to spend much time there anyway," I said.

Luna smiled. "I get it."

As we continued walking, a guy wearing a beanie hat getting closer. When we passed each other, he said to me with a grin on his face, "Long time no see, Geo."

I was shocked, stunned in my step. That voice...I recognized that voice. I immediately looked back, but the guy with the beanie hat had already walked too far for me to see his face.

But that voice was...

Cold sweat began to fall down my cheeks.

"Pluto?" I whispered to myself.

***