"Whoosh --" The sphere fighters galloped like arrows through the night sky.

Frightened William finally got better. He looked at the compass and the map of the sphere fighter, and saw that the next destination was not far away. It was just that he wondered why it was in the shape of a "C" on the map. "We won't know until we reach." He said to himself, losing his height.

As the roar subsided, they succeeded in landing the sphere fighters in front of the "C"-shaped building. Then a camera popped out by the door, and it took a picture of them. After a few seconds, the door slid slowly sideways, signaling them to enter.

As far as the eye could see, there were black patterns in the shape of regular hexagons everywhere, and every vertex was a black circle. In the bright light, a huge white figure was coming toward them. When they were a few meters away, they realized it was a spider robot. It had a crystal black eye, which was a 32K high-definition high-speed camera. It was mounted on a spherical head. The head contained an electromagnet that was connected to the spherical body behind it by electromagnetic force. Inside the body were a small fusion cell similar to Rebecca's, a graphene CPU with a main frequency of 100 gigahertz, and countless tiny steering gear, motors, as well as other components. They drove eight legs mounted on the body and retractable tires below. This allowed the spider to run up to 20km/h on legs, while it was fully capable of sprinting to 80km/h on tires.

Its eight legs moved nimbly. The spider stopped in front of the party, blinked, and said in a friendly way,

"Hello, friends. You guys must have been very frightened, right?"

"Yes, but how did you tell that?" William asked.

"Your little robots told me." Said the spider, "They told me they had been in your backpack for a long time without any communication with the outside world. I have some surprises for you, but not all of them are what you think of as 'surprises'."

"What does he mean?" William was stunned for a moment when he heard the spider's words.

The spider went to a locker and pulled out a minitype black spider robot and a racing plane. "Have you seen these two people?" It asked. Ranran took a closer look: the tiny spider looked very similar to the one they met on the first planet that helped them break into Capsule Laboratory, and the little plane had a blue-and-black paint that looked a lot like Rebecca's fierce rival Jackson.

"Yes," Replied Photon, "but why do you have their models here?"

"You only need to answer one more question. Have you heard frequently a mysterious voice say to your leader, William, 'My plans have been spoilt'?"

Natalie said yes and wondered why the spider knew this, "Can he be..."

But the spider seemed to know what she was thinking. It interrupted, "Oh, don't be nervous. That's what the little robots told me. So it sounds like you're in great danger, doesn't it? Come with me." Before they knew it, the spider was heading for a room, and they had to follow it closely.

"Does he know the planet we've visited?" Ranran muttered doubtfully to herself.

"The little robots told him. I don't think he's any ordinary robot, dear Ranran." There was an odd glint in William's eyes, "I think we could get something very valuable out of him."

The spider led them into a room. Mountains of black objects surrounded them. "What are those?" Aria asked curiously.

"Ha ha, I call this 'the 6th element'. In your language, it's called carbon fiber. You'll think it's nothing special."

Indeed, William's eyes told him it was plain carbon fiber. But his mind detector reminded him, "Don't be fooled by your eyes."

"What's special about that?" He thought.

The spider said, "I've injected some new materials into it, which allows it to 'completely disappear' -- sorry, maybe you don't know what that means. This means that no non-contact detector can detect this material! Don't laugh, it's true! If you don't believe me, you can use this instrument to determine whether there is a fragment of the 6th element on my head."

The spider handed William an integrated detector. It resembled very much a trumpet, and a tube connected to the "loudmouth" was covered with buttons that enabled it to detect signals. Although William cheerfully took it and tried all modes, the detector failed to spot a tiny 1-square-centimeter fragment of carbon fiber on top of the spider's head.

"I'm not dreaming, am I?" William said, aghast.

He reached out and touched the top of the spider's head -- the touch was real. " 'Completely disappear' means that any means of detection other than touch is invalid, William." Laughed the spider, "This material can absorb everything, including electromagnetic waves, sound waves, odorous gases and heats."

"Wow! So does that mean that if someone can't touch something that's covered in this material, they won't know it's there?" Rebecca sort of understood what the spider robot meant.

The spider nodded excitedly, but its smile soon faded. "Want to know why I made it? Come and look at this." Its robotic legs moved slowly in the eyes of the bewildered party, and the camera eye lazily gazed at the floor below it, until it came to a computer. It lifted its front legs feebly, powered on the computer, and opened a file with a strange suffix.

William felt as if the spider robot had become a different person. Before he could think further, a pop-up window on the screen caught his eye.

There was a small black ball rolling fast. It sped past the daunting forests and rolling hills around it, heading straight for a "C"-shaped building.

The camera was extended to check its identity. Instead of cooperating, it stretched out a laser gun and fired madly at the gate. This time the spider robot was enraged. So it strode through the door and fought back.

Bright bullets darted back and forth, the spider and the ball dodging. The robot's body was burned in several places, but its critical parts had not been touched by the wounds. Suffering from a barrage of bullets, it finally destroyed the small black ball.

The ball slowly opened a gap. A few seconds later, a mobile hard disk popped out of there and landed in front of the spider. The spider picked it up and returned to the "C"-shaped building.

Then the window automatically disappeared and was replaced by another one filled with words,

My weapon is almost finished! The "completely disappear" formula has been proven, but I didn't choose to use this material for the ball. The hard disk inside that ball stores the recipe, so as soon as it gets back to me, I can make more balls according to the recipe. But even if it didn't come back, it doesn't matter, because there is a copy in a computer. Yes, I'm just trying to see what a difference this material can make! I can't wait to see the ball right away. Do tremble, aliens! You have spoiled my plans more than once. As revenge, I will spoil yours too!

"Oh dear..." William shivered, "He mastered this technique before the spider robot did..."

Aria and Natalie read the words in horror. "Thanks for your help, Mr Spider," Aria said, "or we'll be in trouble!"

"You're right, Ms Locomotive. But there is one more thing I must tell you." The spider lifted its spherical head and looked into the dark night sky. It said, "Ever since I damaged that little black ball, there has been a constant roar of engines in the air. I don't know what kind of plane it was, but I am pretty sure it is up to no good because it kept circling over my head. I have a hunch that it wants to know what I did to the little black ball. The warning system has been working continuously for about 10 days. I just wish it would go away and never come back."

"No, Mr Spider. The way I see it, that plane isn't targeting you. It is targeting us. So whether or not you managed to destroy the black ball that time and get the 6th element, we have to shoot it down. Otherwise, this crisis will lurk around us like a wild animal until the time is right." Ranran said gravely.

"Better," William added, "we'll delete that copy of the recipe as well. Since that person did not receive the ball, he must try to make some more and test them. This latter part is essential if he wants to get good enough results. Once we delete the copy, his plan will go down the drain."

The spider robot suddenly lit up. A very good idea flashed in front of it. "I've also seen this," It said, opening a document, "but it seems that you can't explain what it means yet."

Strange words appeared on the screen,

The following is the address of the copy file, but it has been compiled into a password. To obtain the password table, you must successfully enter Room -Ts.

070 058 092 084 112 112 083 101 099 114 101 116 115 092 097 112 112 097 114 105 110 103 077 097 116 101 114 105 097 108 092 073 110 103 114 101 100 105 110 116 115 092 105 110 103 046 116 120 116

"And this." Spider Robot opened another file.

The file address is not accessible to other users. Log in with the following username and password to access the address.

Username: 050 051 048 057 049 050 049 050 048 057 057 048 049 049 051 092 050

Password: 048 053 061 049 051 048 051 094 092 050

William took a picture of the words with a little robot. "You may rest assured that we shall ruin his plan." He said with great force, "We'll split up, and soon you won't hear the roar of the engines any more."

"But how do you know where Room -Ts is?" Asked the spider robot.

Natalie showed him the map. "Right here," She said, pointing to a star-shaped sign, "the sphere fighters will go find the plane and shoot it down, while it will be up to us to delete the copy."

"Thanks again for destroying the little black ball, Mr Spider!" Ranran bowed deeply.

"You're welcome. You're going to be on a very dangerous mission, so I suggest you put on the 'completely disappear' clothes." The spider quickly ran over to a pile of carbon fibers and picked out some very large ones. It then placed them over each person, carefully checking to make sure they could only be touched, and finally waved its front legs in congratulations.

"We must hurry." Said William hurriedly, "So we're off now."

"Good luck!" The spider robot looked at the aliens with its camera.

"Poor them," It thought, closing the door and returning to the interior of the building, "troubled by that danger. I wouldn't even know what was going on if their little robots didn't get in touch with me! Poor guys." At this thought, its body rolled violently and its head turned upside down. It said, "I can only pray to God for them, since they have set out."