Half past eight in the morning. British Police Headquarters, Office.

The policeman in a blue military uniform with a calm expression, he said:

"Ma'am, could you please tell me the whole story, please?"

"Y...Yes."

The elderly grandmother in rather luxurious clothes sat in front of him, her voice trembling as she replied. Sitting next to her was her husband, an elderly man who was holding her hand and rubbing it. The two's faces clearly showed a worried expression that could not be hidden.

The grandmother took out a handkerchief from her pocket, and began to recount:

"It happened three nights ago, before that I still saw her sisters going to bed together. But in the morning... my god..." the grandmother buried her face in the handkerchief and burst out. sobbing, can't go on anymore,

The husband was still sitting there rubbing her hand, he continued.

"In the morning, my wife and I didn't see them anymore, the furniture was still there, the room was the same, there was no disturbance. But the bed was empty, both of them. I'm so confused. I don't know where they went..."

The policeman still kept a calm expression, he had been recording the important details of this disappearance in a small blue notebook. He cleared his throat and continued:

"Hem, according to what you said, there isn't any disturbance in the room, so the possibility of a thief sneaking in can be eliminated. But do you think, is it possible that you two went out? Arbitrary out there?"

Grandma was now standing up from her chair, speaking firmly.

"How do you think this is possible? The two grandparents, although old, are still alert and alert as usual. The door is always locked at night and the key is only me or my grandfather. The two of them. No one has the key."

"Are they British? Their nationalities are..."

"Americans. Both of them are Americans. Only their mother was British however she came to study abroad in the US since she was sixteen years old."

William ( the police) nodded and continued to take notes in the notebook, he continued.

"So I guess this is their summer vacation?"

Grandparents nodded.

"I told their parents to come over to England for the summer to play, giving me and my wife the opportunity to talk and visit our two grandchildren. But let them stay in the US, maybe the end of the summer will be close."

Grandfather said, William is now feeling quite confused about the details of the case he is receiving. Strange, if not kidnapping, what is the reason for the disappearance of the two girls? According to the two elderly grandparents, before that, they also saw two little girls going to bed as usual. But in the morning, it disappeared without a trace, everything was still there, only people had disappeared.

[...]

"May I ask more, are these grandparents or parents of the two of you?"

"My wife and I are grandparents of two grandchildren, we are not used to life in the US, so we chose to stay in the UK."

"I understand."

William said though his mind is very hazy right now. It's too hard to understand! How could such a thing happen? If it's an experienced kidnapper, it's only natural that he can sneak in easily. But the strange thing is, the victims here are two girls, one of which is eighteen years old, it has grown up, has consciousness. Not to mention the other two-year-old girl, she also knows the difference between strangers and acquaintances.

Over here, William's mind is still doing its deductive work, the bed, the room is not disturbed, everything is the same. Could it be that both of them didn't know how to scream when suddenly in the middle of the night a stranger entered their room? Or were they both too scared to scream?

This argument is quite correct, William thought to himself. But no matter how scared she is, the older sister, who has turned 18 even if she is too scared to scream, should at least grab something in the room as a weapon to defend herself if she sees that it is a person. It's strange, you can't just sit there like that.

"May I continue..."

William spoke slowly after a long silence.

"You said that this is their summer vacation, so is there a chance that they are hanging out somewhere?"

Another argument popped into his head. Maybe two playful kids, one eighteen and one two-year-old, were just as playful as any other kid. So the possibility that the two of you are wandering somewhere seems reasonable.

These grandparents live in a small village in England, peaceful all year round, fresh air, moreover, this is their first summer vacation when coming to a foreign country. So William is fully convinced that his argument is correct.

"Son, on this matter, Grandpa said slowly, "I'm really sorry, but I think you must have made a mistake, it's true that the two of them have been here during their time here. but those times were all taken by him and he kept an eye on them, not leaving a moment."

At this point, William could not help but be helpless. He looked at the two old grandparents sitting in front of him, he unconsciously let out a sigh. This is the first case with the details that are so mysterious, each of the details mentioned by the two grandparents so far has almost nothing to do with each other.

Shouldn't he be helpless here?

"I think we should go now. Thank you very much, and also sorry for making you lose most of the morning."

Grandfather stood up and helped his wife stand up with him. Grandma struggled to get up, the two of them were about to leave when he suddenly spoke:

"Oh, wait. Don't worry too much, if there is any information about finding the two children, I will report to my family right away. I will do my best."

Grandma looked at him with emotion and then rummaged through her bag for something. After a while, taking out a small card with a light lavender scent, she handed it to William and said:

"Thank you. This is my business card, you can just call the number on this card, okay? Everything depends on you."

"Yes, don't worry. I'll try my best on this case."

He replied firmly. The old woman looked at him with a gentle smile and patted her husband's back, wanting to leave. The old man obeyed, nodded to him, and the two of them slowly led each other out of the police headquarters. William stood and watched the two old figures walking further and further away, suddenly an indescribable emotion rose up in his heart.

How could he deal with this case?