The party, who was frightened out of their wits, flew out of the water, then quickly redirected the sphere fighters, flying toward Hobbs Cave. Once more they saw the dark, scary forest below them, and heard the crows' cries. William did not dare to think of what they had experienced at Black Tower and the sunken ship. Every time he thought of that, he would shiver violently.

A few minutes later, the sphere fighters arrived at the cave. They stopped slowly at the mouth of the cave. The party saw a bird fly out of the hole and land in front of them.

"Here you are at last! I'm Charlotte." Said the bird with relief, signaling the others to go into the cave.

There were some patterns on both sides. They would have been willing to look more closely to see what the patterns were, but right after seeing the first picture, William turned his head away and did not dare to look any further. In the first picture, lots of red seagulls were killed by an unidentified creature. The bright red blood gushed out. "These are true stories that happened to us! Please do help us!" Said Charlotte in a tearful voice.

"Please do not be sad, dear Charlotte. We'll find a way." William replied firmly.

Charlotte led them into a small room. "I suppose you've all been to the sunken ship just now, right?" She asked.

"Yes." William replied, "We also found some bird bones, which really puzzled us."

"Oh, you stole my lines." Charlotte joked, "I'm about to say something about bird bones. Well, that's actually my compatriots."

"What?" Ranran was frightened and turned pale.

"That really is my compatriots.

"One day we woke up, finding a red seagull missing, so we anxiously went out to look for him. But after walking only a few steps, we felt dizzy. At last all the red seagulls fainted to the ground.

"When we woke up again, we found that some more red seagulls were gone and their remains were not far ahead. We couldn't believe it, so we ran over and shook them violently, trying to wake them up. But it was all in vain, for a note said,

"Don't make useless struggles. Your compatriots have rested in peace. If you still want to know where the most-firstly-died compatriots were buried, then I can tell you the answer. Go look for the sunken ship, and then you'll see their remains. But I strongly do not recommend you to do this, because the compatriots who will go to look for the remains may also end up dying here!

"Anger and sorrow overcame our fear of losing more of our compatriots, especially when the original population was small. Some red seagulls found the ship and did find the remains, but they couldn't get out either!

"We lost a lot of our compatriots every day for many days! Do you know why we are hiding in this cave? That's because we have to escape the killings of that creature. The cave was built only a few days ago, and since then, the creature has not visited. At last we have a chance to break! Dear me, I do not dare to think of whether we shall survive if we go out!"

Charlotte could no more control her emotions. Round tears fell from her shining eyes.

"Don't be sad. Can you tell us something about the creature?" Ranran asked softly.

"The creature left no message. However, from the condition of the remains, it looks like they were hit by a laser because you can see a lot of charred notches."

William thought carefully. "Laser? Wait." He grew nervous, "I guess it's not done by creatures. Do you guys think the so-called creature could be something like our sphere fighters?"

Photon nodded, quite agreeing with his master's hypothesis, "I think so too, and I think it's equipped with weapons similar to ours. Charlotte, do you still have access to the remains of your companions? We want to test what kind of weapon could cause that kind of damage."

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Charlotte found a remain in the room and dragged it out. She said, "I think you've got a good point. At first we all thought that a creature had killed our compatriots. However, after examining the remains, we have a similar idea, for there is no creature on this planet capable of producing lasers."

The sphere fighters fired some bullets, but Rebecca was quick to dismiss the hypothesis, "The wounds weren't big enough. I want to try it with a laser missile."

"Me too." Photon volunteered, but the result was disappointing -- the wounds caused by laser missiles were a bit bigger. Aria also discovered that the wounds on the remains, though small, were more fatal than those caused by the laser missiles.

At this point, the party was completely confused. What weapon on earth killed the red seagulls? But they were sure that the wounds were caused by the heat.

"So that weapon is unknown to us, I think." Ranran came up with this idea.

"Yes, I agree with Ms Ranran." Aria said, "And I personally don't think it generates heat in the same way as any weapon we have now. Robots in the arsenal have told us that laser missiles contain small hydrogen bombs. You must have seen the killability of them when we fought against the drone fighter. But the facts tell us that this unknown weapon can do smaller but more fatal damage."

For a moment William could not think of any way to do that kind of damage. He began to walk about, racking his brain as he walked. By chance, he spotted a nearby checkpoint on the computer map.

Checkpoint 34 is cleared. Energy charge: 2%.

Something drove him to think of the base of the shark, jellyfish and whale that he had just encountered. Since it looked so much like their undersea villa in the trinary system, his mind drifted to the undersea villa. "I remember that's where we got the energy core," He thought, and made sure his memory was correct.

While William was resting, he was implanted with a mind detector. At this time, it reminded him, "Is there anything that came together with the energy core?"

"Something that came together with it? ..." He strolled about, clapping his hands and saying,

"That's right, the instructions for the energy core!"

His voice was so loud that the others were frightened. They looked at him in wonder. "Is there anything special about the instructions?" Rebecca and Aria asked.

"Oh, you don't know that." William replied, "If my memory is correct, I think the instructions say that the energy core runs on negative energy... Wait a minute, negative energy?"

The mind detector projected a particular picture. It was a diagram of a hydrogen atom. One proton was in the middle, and one electron went around it.

There were more and more protons, and neutrons showed up. Meanwhile, the number of electrons was increasing. So he saw the microscopic structures of all the elements in the periodic table of elements.

Then, all the particles disappeared, and in their place were again the structure picture of hydrogen atom. When he zoomed in the picture, however, William noticed a difference. In the previous pictures, protons had positive charges and electrons negative. Now it was just the other way around.

"I seem to have found the answer," He thought. Then he asked Charlotte, "Did your dead companions become dizzy, get frightened, and hear voices?"

"It seems they almost all feel the same way."

William regarded this as a serious problem. These symptoms were very much like how he acted when he was threatened by You-Know-Who. What's more, in this picture he saw particles with the opposite charges, which were called antimatter. He already knew about positive energy, so he ventured to guess that antimatter had negative energy, which he had never considered before.

Though it was only a hypothesis at the moment, yet somehow William felt that it was the truth. For an instant, a rush of cold crept into his body, drilled into his bones, and hurt him like a sharp drill. He fell to the ground, clutching his arms and breathing hard.

Ranran ran over at once and looked at William with concern. "Are you all right?" She asked anxiously. "I... I'm fine." William gasped.

The coldness left. He stood up and pressed his still painful arms. He dared not dwell on his terrible hypothesis any longer, and he preferred it to remain a hypothesis. But he wasn't sure whether he'd miss the truth.

"Charlotte, we have a very bad feeling." William said nervously to the red seagull, "That creature may have a very powerful weapon. And based on my previous experiences, I fear that he will not only exterminate you, but all other creatures as well."

"Oh God!" Charlotte's voice shook violently, "I hope it's not true!"

"We don't have enough clues yet." Natalie came to comfort her, "You just need to stay in this safe cave. We will continue to search for more clues to determine the identity of the creature. Once we find out, we will fight him to the end!"

"Fight to the end!" Shouted the others. Their voices were so loud that the ground shook.

Natalie continued, "We have a cloning technique that uses cells to produce individuals. This will greatly ease your anxiety." William obtained one of Charlotte's cells and put it into the cloning machine. A few hours later, countless baby red seagulls bounced happily out of the machine.

Charlotte the red seagull was grateful.

Ranran told her, "You go inside quickly before that creature finds another chance to kill your compatriots. Protect well your children! We need to travel, so we won't stay long with you. Rest assured, you will be safe!"

Charlotte the red seagull thanked excitedly. She watched the sphere fighters disappear from her sight.