Chioujen checked the room behind the elevator. Indeed, there were parts that protruded inward. The room that contained the elevator was the exact size as depicted in the floor plan they had seen. Two service elevators were located in a row. So, the room designated as the location of the lift service had dimensions of about four by six meters. But what was actually used for the elevator was only four by three and a half meters. So, there was still a space of about four by two and a half meters that Chioujen didn't know its function. Except for the elevator door, there was no other door to enter the space.

Chioujen got back into the elevator. He looked at the ceiling of the elevator. It was not like in movies, which often depicted how easy it was to open the elevator ceiling from the inside. The ceiling in this elevator seemed solid. It could not be opened from the inside. Chioujen was silent while racking his brains to find the other entrance.

"Top floor, Sir!" Suddenly Hannrong broke the silence.

"You mean we can check this elevator room from the top floor?"

This kid's suggestion makes sense!

Hannrong nodded. "I remember when a technician came to fix the elevator. At first they always went upstairs if they wanted to check the inside of the elevator."

"You mean the twelfth floor?" Chioujen asked for Hannrong's confirmation.

"No, Sir! The twelfth floor is the last floor that can be reached by the elevator. Above that, there are still several rooms whose function I also do not know clearly."

"You mean above the twelfth floor there is still a thirteenth?"

Although he had come to this building several times, Chioujen had never once climbed to the roof. So he really didn't know.

"No Sir! The twelfth floor is the last floor. Above it, there is only a roof. However, in some parts of the roof there are small buildings that I do not know their function. Maybe some of them are used as warehouses. There's a room right above the service elevator, occupant elevator, stairs, and emergency stairs. The technicians usually checked the elevators from there."

"Those rooms must be locked, right?"

"That's right Sir! It's locked."

"Do you have the key?"

"I only have the keys to the rooms whose positions are the stairs and the fire escape on the roof, Sir."

"Then, the other rooms. Who holds the keys?"

"The Managing Manager should be the one holding the keys. However, since there is currently no Managing Manager, the building owner is the only one holding the keys to the rooms on the roof of this building. He also holds the keys to the rooms on the floors below this ground floor. When a technician came, a representative from the building owner always came with the keys. After the technician finished work, the representative from the building owner took the key away again."

"Then, let's go upstairs. At least I'll have to see by myself."

"Okay! I'll take you up," said Hannrong.

Before leaving, Hannrong turned off the lift service. He then carried Chioujen up to the twelfth floor via the resident elevator. Arriving on the twelfth floor, Hannrong guided Chioujen to the roof via the stairs.

"Ah! So this is how things are on the roof!" Chioujen looked around after they reached the roof.

Just as Hannrong had explained, several small buildings were on the roof. Chioujen looked at the place they had just passed. The place, namely the building that housed the stairs, was also one of several small structures on the roof. Hannrong walked to another building which was directly above the service elevator.

"This is the place, sir." Hannrong pointed at the building with his index finger after they arrived there.

Chioujen surveyed the building. Its dimensions were slightly larger than the dimensions of the service elevator, as shown on the building's floor plan, approximately seven meters by five meters. It was about four meters high. There was a door in what appeared to be the front.

"The technicians came in from this door, sir, when they had to repair the elevator from the inside," said Hannrong.

The front part of this space must have been a cavity whose upper part was used as the end of the hook to hang the elevator. As for the back part, it is the entrance to the mysterious room we're looking for!.