Fraternal twins Aya and Aki Mikage leave a karaoke bar with three of their classmates. As they are crossing a bridge, they see a man ahead of the other side steal a woman's purse and run towards their side. Aya runs forward and tackles the man, knocking the purse out of his hand. She tries to catch the purse, inadvertently jumping over the side of the bridge. As she falls towards the busy street below, she finds her mind filled with strange images, including a symbol she's never seen before. Suddenly, she stops falling and begins floating instead, landing gently on her feet. A stranger then saves her life by pushing her out of the path of a car, then disappears before she can thank him. The next day, Aya and Aki go to their grandfather's house to celebrate their sixteenth birthday. They are surprised to find that many of their relatives are there for the party. They are given a single present, a wrapped box. As she unwraps it, Aya becomes increasingly uneasy. Aki volunteers to open the box instead. Inside is a mummified hand. Aya experiences another blur of strange visions, her shirt sleeves rip, and for a moment her eyes change from bright blue to deep gold. She sends out an incredibly strong and powerful burst of highly destructive power that destroys the hand, then returns to normal. Confused, she turns to Aki to ask what happened, but Aki is writhing in pain as cuts begin appearing all over his body. Aya screams to her family to help before he dies, but no one moves. Her grandfather tells her the marks are a sign that Aki is the rightful heir of the Mikage and he will be fine, but that she must now die.