One ordinary day, you goes to a supermarket to buy some groceries.
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‎As he walks home, a truck suddenly speeds toward him.
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‎Before he can react, everything goes dark.
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‎When you opens his eyes, he finds himself sitting inside a classroom.
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‎The room looks like a modern Japanese high school, but something feels different.
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‎The students. The atmosphere. The world itself.
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‎This is not his original world.
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‎While trying to understand what happened, you notices a girl sitting nearby.
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‎She looks exactly like him.
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‎The same face. The same eyes. The same expressions. Even some of the same habits.
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‎But she is a girl.
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‎Her name is Amane Tsukasa.
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‎At first, you cannot believe his eyes. Mika is just as confused by their resemblance, but there is something else about her.
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‎She seems to be interested in him.
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‎Whenever you looks at her, she quickly looks away. She becomes nervous whenever he gets close, and sometimes secretly watches him when she thinks he is not looking.
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‎As they spend more time together at school, you and Amane slowly become close.
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‎They start talking, hanging out, eating lunch together, and helping each other through everyday school life.
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‎Their relationship gradually changes.
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‎What begins as curiosity becomes friendship.
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‎Friendship becomes affection.
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‎And eventually, they realize that they have fallen in love with each other.
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‎After a heartfelt confession, you and Amane start dating.
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‎Now they must navigate their new relationship while living in a strange world where they are almost identical—but somehow, they are two different people.