Seras Tu Là? by Guillaume Musso

An aging surgeon receives mysterious pills from a man whose life he once saved, enabling him to travel thirty years into the past and meet his younger self. Given a chance to prevent the tragic death of his first love, the two versions of himself try to rewrite fate, but each change threatens the future he cherishes—including the daughter and friendships that define his life—forcing him to reckon with love, destiny, and the price of second chances.

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