Could the water above the sea line flow under it, causing the lower water level to rise? How is that possible?
Tilly pondered for a moment, "Then what about the ebb tide? Will the seawater flow backward?"
"Good question!" Thunder excitedly clenched his fist. "After that, my fleet stayed near the sea line for half a month, until the tide receded. During this time, I also used various methods to cross the sea line. The most amazing thing was sailing on the sea line—do you know what that feels like? To outsiders, we seemed to be stuck on a cliff face, with our sails completely parallel to the sea, as if we could fall off at any moment. But those of us on the ship couldn't feel it at all. The Courage was like sailing on a narrow waterway a few feet wide, with an endless wall of seawater on one side and a vast sky on the other. Of course, we had to wait for the water flow to slow down before doing this, otherwise, the magic servants wouldn't be able to protect the hull."
"This... it's completely against common sense." Tilly felt a mess in her mind. If the narrator wasn't Thunder, but some other explorer, she would have thought he was just bragging.
"I think so too, but I trust my own eyes more than common sense." He continued, "Half a month later, the tide began to recede—very punctually, just like the tidal timing of the Shadow Islands. The seawater didn't flow backward either, it just slowly retreated, and the sea line rose from a few feet high back to dozens of feet."
"Are you saying that the extra seawater just disappeared into thin air?"
"Perhaps, but it might have flowed somewhere else."
"Where could it flow to?" Tilly rubbed her forehead. "The tides of the Shadow Islands rise and fall dramatically, while those of the Fjord Islands are much gentler. By the time they reach the shores of the Four Kingdoms, there's almost no noticeable change—isn't this just disappearing into thin air?"
Thunder pointed to the ground.
She sighed, "Oh, I remember you saying that the water level in the Shadow Sea drops so quickly that it's as if there's a huge hole in the seabed swallowing seawater. But even if this hole is huge, it should be filled up in a few years."
"That's just my guess, after all, no one has ever seen what the real seabed looks like, but... there's one thing that bothers me."
"What?"
"That is, why is the ocean we're in called the 'Vortex Sea'?"
Tilly was startled to hear this, then shook her head. "Impossible, that idea is too crazy. If underwater cave drainage could cause whirlpools, how could we not observe them? Besides, this name has been around for hundreds of years, who knows what the namer was thinking at the time."
"Indeed, I've done simple experiments, and you can only see whirlpools when the water is shallow enough, and we don't have the ability to go deep into the seabed." Thunder smiled mysteriously. "But we don't, doesn't mean witches can't—I hadn't thought of this before, but when you told me that there was a witch empire that spanned the continent more than four hundred years ago, I realized that this name was very likely passed down from that era."
"But I am a witch," Tilly shrugged. "And there's no witch on Sleeping Island whose ability can do that."
"I do know one."
"What?"
"This witch is in the Fjords, but she hasn't been in contact with humans for a long time..." Thunder sighed. "She was a good friend of a capable deputy in my expedition team. Since awakening as a witch, she has permanently bid farewell to the land. Now, you can only hear her melodious singing when the waterway is foggy. You should have heard her story as well."
"The mermaid who guides the route... are you talking about the protagonist of this legend?"
"That's right," Thunder nodded. "Although I don't know if I can get her help, I have to try. Maybe I'll need my old friend Mageli to help me out with this."
"I see, then you have to hurry," Tilly frowned. "It seems that some people in the Fjord merchants want to get their hands on the mermaid. A month ago, 'Sleeping Spell' received several commissions to hire witches to capture mermaids. Mitang specially sent a messenger to ask me for instructions, but I rejected them."
"Her singing is regarded as a symbol of good luck and peace by all Fjord sailors and explorers. These merchants are simply crazy," Thunder asked in a deep voice, "Can you tell me who they are?"
"'Sleeping Spell' shouldn't disclose the identities of its customers, but..." Tilly drew a few names in the air. "You just happened to see it yourself." Since the other party was a witch, as the leader of Sleeping Island, she couldn't sit idly by.
"That's right," he raised the corner of his mouth. "They will be punished."
The two smiled at each other, and Thunder then said, "Besides the new exploration commission, I have something else I need your help with this time."
"Speak."
"It's like this, after I came back, I heard that Crescent Moon Bay has introduced a new type of ship that can sail without relying on wind power and is much faster than sailboats. I asked someone to inquire about it in detail and learned that this ship was actually made in Border Town," Thunder said frankly. "If I want to continue exploring above the waterline, I must have larger and faster ships, otherwise, in the case of poor wind power, I can only be pushed back by the current." He took out a letter from his arms. "Money is not a problem, the faster the ship, the better. Can you help me give this order letter to him?"
Tilly quickly understood what he meant. "You don't want Lightning to know?"
Thunder said helplessly, "If she knew, she would insist on going with me. No one knows what's above the waterline, and I can't take her on an adventure."
But she is already a qualified explorer. The stone tower ruins hidden deep in the Misty Forest were her discovery, Tilly thought, and finally nodded. "I understand, I will contact Roland Wimbledon for you temporarily."
"Thank you, Your Highness."
After Thunder left, Tilly pondered for a long time and brought out the ancient books from the ruins of the Shadow Islands again. Perhaps she could find clues related to the sea line and tides in them. According to Agatha's teaching method, she twisted the magic power according to the shape of the characters, and the corresponding meaning automatically appeared in her mind—as if she was not reading a book, but the book was telling her its content.
Some ancient descriptions recorded what the recorder saw and heard in the Wilderness, some were like nautical logs, and some mentioned the Federation's reconstruction plan. The more she read, the more confused she became. There was no connection between these contents, and they didn't seem to be written by the same person. Moreover, none of them mentioned the sea line, the underwater spire, the telescope, and the huge stone gate in the mirror. This was completely different from what she had expected—she originally thought that as long as she could understand the Federation's text, she would be able to uncover some of the secrets in the ruins, and even find out the truth about the rapid rise and fall of the sea level in the Shadow Sea. But now, she was more like flipping through a pile of pieced-together notes.
Wait... pieced together? A flash of lightning suddenly struck Tilly's mind. She spread out three nautical logs together and carefully checked them again—the times recorded on them were very different, some even decades apart, and the routes were also different, from the sea area near the mainland to the Fjords, as if someone had collected these things little by little and then stored them in the ruins.
When this thought came to her, she couldn't help but feel a chill rising from her back.
Who on earth would do this?(。)