It was just another ordinary afternoon. Leon was looking after his young cousin, Ethan, at his parents' request. He had taken charge of the boy while his parents were away on an overseas business trip for the summer. Aria was in a similar situation. Her parents, both researchers, had to attend an international conference on short notice, leaving her to care for her cousin, Eugene. The two didn't know each other, nor did they even realize they lived in the same city. Everything was normal. Until the breaking news hit. "This is an emergency broadcast." The TV screen suddenly cut out, replaced by an announcer's trembling voice. "Unidentified flying objects have been spotted over major cities worldwide." At first, everyone thought it was a prank. Maybe a movie shoot. Maybe a military exercise. That's what some people said. But a few minutes later... What the cameras captured was definitely not human. Colossal metal structures were piercing through the clouds, and unidentified lifeforms began attacking the city. Buildings crumbled. Communication networks went down. The streets were filled with screams. In that moment, Aria's phone rang. It was her mother. The connection was unstable, but her voice was clear. "Aria, listen carefully." Her mother's voice was grave. "Do not go outside under any circumstances." "Mom?" "Go to the underground bunker." "What are you talking about?" "There's no time to explain." A moment of silence followed. Then her mother spoke one last time. "What we were researching... it has become a reality." The call cut off. Aria stood there, frozen. Her researcher parents had been conducting studies on strange space signals and extraterrestrial life for years. But she had thought it was just academic research. She never imagined it would be real. Inside the emergency kit her parents left behind was a strange card. A hidden elevator that opened with that card. And a massive bunker located deep underground. It was as if they had been preparing for this day for a long time. Hours later. Aria entered the bunker with her cousin Eugene. To her surprise, there were already others there. Among them were a young man with blond hair and blue eyes, and a young boy. It was Leon and Ethan. The heavy iron door closed. Thud. The last bit of light vanished. Silence descended upon the bunker. At that time, no one knew. That this place was not just a simple shelter. And that the research Aria's parents were hiding was linked to the fate of humanity. Outside, the alien invasion had begun, And inside, a much more dangerous truth was awakening.