The aroma of takoyaki and yakisoba hung in the air, mingling with the sweet fragrance of thousands of cherry blossoms. Maruyama Park in Kyoto was a hive of activity, a sea of kimonos and laughter celebrating Hanami, the spring festival. The sun shone brightly, but a gentle breeze caressed their cheeks, bringing with it the perfume of flowers and the promise of new beginnings.Ren Takahashi, a university student with a kind face and tousled brown hair, made his way through the crowd with his little sister, Aiko. She, with her boundless energy and her two pigtails dancing to the rhythm of her steps, pulled his hand impatiently. Ren felt the warmth of Aiko's hand in his, small and soft, but with a surprisingly strong grip."Onii-chan, hurry up!" Aiko exclaimed, her eyes sparkling with excitement. "I want to see the Sacred Sakura! They say that if you make a wish there, it will come true!"Ren smiled indulgently. Aiko and her whims... Always so full of fantasy. Although, looking at the majesty of the Sacred Sakura, an ancient cherry tree with an imposing trunk that dominated the park, he himself felt a pang of wonder. It was as if the tree emanated a special energy, a connection to something ancient and powerful. The branches, covered in pink and white flowers, stretched towards the sky as if they wanted to touch the clouds."Wait a minute, Aiko," said Ren, trying to restrain his sister. "There are a lot of people..."But Aiko, ignoring his words, slipped through the crowd like an eel, dragging Ren behind her. He followed her, dodging passersby and smiling apologetically at those Aiko accidentally bumped into. Finally, they reached the base of the Sacred Sakura. Aiko, her mouth agape, gazed at the tree with reverence."It's huge, Onii-chan... It's like a giant!"Ren nodded, impressed. He had never seen such a majestic tree. The rough bark, rough to the touch, the branches that stretched towards the sky like arms, the delicate pink flowers that fell like a soft rain... It was a hypnotic sight. The air around them seemed to vibrate with an invisible energy, as if the tree itself were about to awaken from a long sleep.Aiko, with her hands clasped together, closed her eyes and murmured a wish. Ren couldn't help but smile. What would his little sister be asking for? A new toy? A lot of candy? Maybe a puppy, Ren thought, remembering how insistently Aiko had been asking for one lately.Suddenly, a golden glow emanated from the Sacred Sakura. The people around them stopped, watching in amazement as the tree lit up with a supernatural light. An intense hum filled the air, a high-pitched sound that seemed to come from the depths of the earth, and a vortex of energy opened in the trunk of the tree, spinning like a whirlpool. The vortex, an intense golden color, seemed to absorb the light and sound around it, creating a sense of unsettling emptiness.The crowd panicked. Screams and shoves followed as people tried to get away from the tree. Ren, terrified, felt a chill run down his spine. His heart pounded in his chest, and a knot of anguish formed in his throat. He searched for Aiko with his eyes, scanning the frantic crowd, and then he saw her, a few meters away from him, being dragged towards the vortex by an invisible force."Aiko!" Ren shouted desperately. His voice was lost in the screams of the people, but he kept shouting, hoping his sister would hear him.He lunged towards her, trying to reach her, but it was too late. His fingers brushed the sleeve of Aiko's kimono, but he couldn't grab her. Aiko, her eyes filled with fear, disappeared into the vortex. A moment later, the portal closed with a thud, leaving behind a deathly silence and an immense void in Ren's heart. The world around him seemed to have stopped, and he stood there, paralyzed, his arm outstretched towards the spot where his sister had disappeared.Chaos reigned in Maruyama Park. The sirens of ambulances and police cars broke the silence left by the vortex. The people, shocked, gathered in small groups, commenting on the strange event in hushed voices. Some cried, others prayed, and many simply observed the Sacred Sakura with a mixture of fear and fascination. The festive atmosphere had completely disappeared, replaced by an atmosphere of confusion and fear.Ren remained motionless, staring at the spot where Aiko had disappeared. The words of the police officers who surrounded him, asking him what had happened, and the paramedics who tried to examine him, reached him like a distant echo. He couldn't process what had happened. His sister, his little Aiko, had vanished before his eyes. Guilt gnawed at him. Why hadn't he held her tighter? Why had he let her run towards the tree?Suddenly, he felt a hand on his shoulder. A firm hand, but not aggressive. He turned and saw a woman in her thirties, with black hair tied back in a ponytail and dark eyes that conveyed intelligence and determination. Her face, although serious, showed a deep sadness, as if she had known pain closely. She wore a white coat and carried a briefcase."I'm Dr. Sato," the woman said, her voice firm but with a touch of warmth. "I've heard what happened. Can you tell me what you saw?"Ren looked at her with suspicion. Who was this woman? And what could she do? Her eyes, however, conveyed a confidence that reassured him somewhat."My sister... The vortex..." Ren stammered, unable to form a coherent sentence.Dr. Sato nodded in understanding. Her eyes fell on the Sacred Sakura, and a shadow of pain crossed her face."Calm down," she said. "Take a deep breath. Everything will be alright."Her words, spoken with surprising calmness, had a calming effect on Ren. He felt he could trust her."We were in front of the tree," Ren began to explain, his voice still trembling. "Aiko wanted to make a wish... And then... The tree started to glow, and a hole opened... A vortex... And Aiko..."Dr. Sato listened attentively, without interrupting, her gaze fixed on Ren, as if trying to read his thoughts. When Ren finished speaking, she nodded again."I see," she said. "It's an extraordinary phenomenon. But don't worry, we'll do everything we can to find your sister.""Really?" Ren asked, a glimmer of hope in his eyes."Of course," replied Dr. Sato, with a slight smile. "I'm the director of the paranormal research department. We've been studying phenomena like this for years."Dr. Sato opened her briefcase and took out a small sphere-shaped device. The device emitted a faint blue light, pulsing like a heart."This is a dimensional tracker," she explained. "If we can activate it near the vortex, we might be able to track your sister's energy and locate her. But first, you'll need to prepare yourself. You'll have to undergo rigorous training before entering the vortex."Ren felt hope reborn within him. Perhaps there was still a chance to get Aiko back. A new determination took hold of him."Please, Dr. Sato," said Ren, pleading in his voice. "You have to help me.""I will," replied Dr. Sato, with determination, her eyes reflecting the same flame of hope that burned in Ren's. "I promise."