Fifty years ago, Clara lost her beloved mother, Rita. Rita's death left a mystery that puzzled Clara, and she was haunted by the shadows of a woman who always watched her wherever she went.

After the collapse of the Underwater City, which claimed a life, all the sirens no longer wanted to stay there. However, Clara was convinced that her mother's death was not due to the disaster that struck at that time but was caused by a siren named Thalassa.

"We need to find another place, Clara. They're traumatized living here," George said to Clara, who looked confused and alone.

"No, George. I don't want to take the risk; it's not safe for sirens out there. I don't want to deal with humans."

"We won't be dealing with humans. We need to find another place, but it must be in the depths beyond human reach."

Clara contemplated George's words. She began to think about returning to Atlantis and rebuilding the city. However, Clara had to negotiate with the residents of the Underwater City. Not all sirens wanted to move to Atlantis.

Indeed, when Clara announced the plan to move the residents to Atlantis, many of them refused to leave. They preferred to die there rather than return to Atlantis.

With provocateurs making the situation even more heated, Clara became increasingly confused and angry.

"QUIET!" Clara exclaimed. Instantly, the previously chaotic atmosphere fell silent.

"Listen to me! I've decided to move to Atlantis because there's no safer place for us. In a situation like this, you're forcing me to find a safe place for us. But after I find it, you refuse and choose to die here! If that's how you feel, find a wiser leader who can keep you safe anytime, anywhere," Clara continued. The blonde-haired girl was so frustrated with the residents, unlike her usual self.

After saying this, Clara left them and returned to her room to calm her thoughts. Rick, who had never seen Clara so angry, immediately approached her.

"What are you hiding, Clara?" Rick asked.

"I need some time alone. Can you please leave?" Clara even pushed Rick away, who was trying to comfort her.

"No, Clara. You don't need time alone; you need a friend to talk about your problems." Rick, who had been friends with Clara for decades, didn't want to leave her in this state.

After being persuaded several times, Clara confided in Rick. It turned out that Clara was constantly haunted by her mother's death, who kept mentioning the name Thalassa. Clara was convinced that a siren named Thalassa was the shadowy woman who always disturbed her. However, Clara had never seen Thalassa's true form.

Clara's uncontrolled emotions were due to her constantly hearing her mother mention the name Thalassa. However, she didn't know where to start looking. It was impossible for Clara to explore the vast ocean.

After hearing everything Clara had to say, Rick promised to help her, even if it meant venturing into the ocean alone to find the siren named Thalassa.

Clara, who had been consumed by emotions earlier, was now calmed by Rick. She just needed a friend to confide in. After everything had improved, she felt guilty for scolding the residents of the Underwater City. She immediately went out to apologize.

The residents accepted Clara's apology with open hearts. Likewise, Clara forgave the residents who had protested too much, causing her frustration.

With confidence, Clara reaffirmed her determination to move the residents to Atlantis and rebuild the siren kingdom there.

...

An old woman was sailing alone in the middle of the ocean, and faint glimpses of sirens were seen swimming beneath her boat. However, the old woman didn't appear to be afraid. She actually smiled when she saw the siren shadows.

The old woman's smile didn't deter the siren with malicious intentions; in fact, the siren suddenly leaped from the front of the old woman to drag her underwater. But right in front of the old woman, the siren about to capture her was suddenly struck by lightning and thrown back into the sea, even though the weather was clear.

The appearance of the lightning wasn't without reason; a woman descended from the sky and stepped on the water's surface. A woman with brown hair and the appearance of an angel asked about the purpose of the old woman's visit.

"I'm looking for sirens," the old woman replied.

"What do you mean? Aren't you afraid of sirens?" the beautiful woman asked again.

"Why should I be afraid? Not all sirens are evil; I just want to meet my old friend."

"Who is your old friend? Maybe I can help you find them."

"Clara," she answered.

...

All the residents of Underwater City have arrived in Atlantis, as they expected, and there is not a single building left there.

Some residents appeared disheartened when they saw the condition of Atlantis. In fact, they wanted to return to Underwater City, where they clearly had homes. However, Clara and her friends never tired of encouraging all the sirens there. Soon, all the sirens regained their enthusiasm and began building structures one by one.

Amidst watching the others work, Clara's instinct told her that there would be uninvited guests coming to Atlantis. She began to feel uneasy but tried not to show it in front of the other sirens.

"Hey, you seem to be looking for someone. Who are you looking for?" George asked, noticing that Clara was acting a bit strange.

"Oh, George. No, I'm not looking for anyone. I just want to see that the residents are here," she replied.

"Oh, really? Your lying skills are terrible, Clara. Come on! What are you hiding?"

"Ah, fine. I sense that there's a stranger heading this way."

"Do you sense their energy? Is it positive or negative?"

"I can't sense anything from them; it's very strange. This is the first time I've felt like this, and I can't even track their whereabouts."

Hearing Clara's explanation, George suggested that she put a magic spell at the entrance to Atlantis. It was a brilliant idea that Clara accepted.

Not only did Clara cast the regular siren spell, but she also layered it with her own spell called "defensionis." Apart from repelling intruders, this spell would be difficult for anyone to penetrate. Moreover, if someone managed to break the spell, Clara would feel it herself.

Shortly after setting up the spell, Clara returned to help the others build Atlantis with her magic. While working on the construction, Clara sensed that someone had successfully broken the "defensionis" spell.

"Stop working and get ready! There will be uninvited guests arriving here!" Clara shouted.