Approaching the solution

He stood in front of the door catching his breath, then headed towards the bookshelf and started counting and searching.

He found the shelf and took out all the books that were placed in it. He searched the shelf itself but found nothing. Then he started searching through the books.

It took him all evening and he didn't finish 1/3 of the books because he had to search every page.

He heard the door open, he stood tiredly and left the office. He found that his mother had returned. "Hello mom, how is Sophia?"

"Good, she's asking about you, you should visit her soon." Rose removed her shoes as she spoke, she looked tired.

"Yes, I will visit her tomorrow." After he agreed, he was going to return to the office.

"The school told me that you were absent this evening." Rose stopped him and spoke seriously. "Where were you?" This is the first time you've done this and you're absent.''

''Sorry.'' Karl didn't explain to her, he just apologized.

''I'm not stopping you from following those illusions, it's better for you to give up on your own after searching for a while, you're my son and I know you're stubborn and won't listen to me,

But if there's another time or your studies are affected, you'll be banned from getting close to everything related to your father and you won't be allowed to search into this matter again, is that understood?

Rose was angry and spoke seriously, she lost her husband because of these delusions and she doesn't want to lose her son too, she doesn't want to interfere in his choices but if it's necessary she will interfere

''Yes'' He lowered his head then waited until she left, then ran towards the desk and continued searching

When he picked up the next book, he found that it was full of blank pages, he turned the pages and found them all blank, then he thought that it might be like a safe in the garage

So he took out the tool again and searched for any words written in his father's secret ink

And indeed he found it on the fifth page, it was the phrase "I'm sorry, my son"

This time too it didn't take him long to know what it meant, he had a wound on his head covered with hair due to an injury when he was young

And his father always apologized when he saw the wound, now that he was thinking about it, he started to shiver as he thought,

Then he moved his head and removed this stupid idea, his father couldn't do this and his head was small and couldn't fit a map.

Karl didn't know that his thinking was strange, why didn't he think that the problem was that he might die if this happened.

The important thing is, after some thinking, there was no answer to this puzzle other than that place, ''I promised her, but it seems that I will have to lie to her. '' He sighed as he thought about his mother, she wouldn't let him go so he would have to sneak in.

Now he just needed to think about how he would do that and avoid trouble at the same time.

The next day, Karl went with his mother to visit Sophia in the hospital, she was lying on the bed weak.

Karl approached her with a gentle smile, ''Sophia, how are you now? ''

''Huh? '' Sophia turned her head to the side angrily, she looked angry and didn't want to see Karl.

Are you mad at me because I didn't visit you this week? , "Okay, sorry," Karl apologized as he held her hand but to no avail, she weakly pulled her hand back and turned around while avoiding him.

"Huff,"

"Unfortunately, it seems that I will return this chocolate that I brought, maybe I will distribute it to the other children in the hospital," Karl sighed as he held the bag in his hand and headed towards the door.

Sophia struggled for a second but gave in to the temptation of the chocolate, "Stop, it's mine, as long as you brought it to me, it's mine."

Karl and Rose laughed then he gave her the bag and helped her open it, "Huff, I'll forgive you just this once, but I won't forgive you next time."

"Okay, okay," Karl spoke submissively and gave in to her complaints, then he started talking and telling her stories and playing with her until she fell asleep.

After covering her, he went out To find his mother talking to the doctor

Karl remained silent all the way, when they arrived home he said to his mother "Mom, will Sophia be okay?"

His mother was silent for a while then put her hand on his head and spoke firmly "Yes" but there was a note of crying in her voice, however she tried to remain strong in front of her son

Karl was not stupid, but he stopped talking and entered his room, he looked out the window at the place where his sister used to play when she was healthy

But then he sighed helplessly, even if he was smart he was young and even if he wanted to treat her, he had no way to even study his sister's condition and try to treat her, and this would take time and he was only 12 years old

He quickly pushed these thoughts out of his head and started thinking about how to sneak into the place in the puzzle, and when he found the ship he would take his sister to see her