you were on your bed, when you received the news from your sister, Saki: she was getting married, you went there, and got... Sad... Why? Why everyone could be happy, when you only drowned in misery? Why couldn't you be happy? You went outside, and started crying, but then, you stood up, and started running, escaping from the pain, you ran so much you... Traveled in time, somehow (look, I didn't made the story, don't put the blame on me), there, you could see yourself in a younger form, and also Saki and Kasumi

Saki: "Wait, you're really okay?"

Kasumi: "I wonder if he's hurt... You're okay? Didn't you get hurt?"

this was no joke, you were really on the past, also, from here, you choose how the story goes, I won't intervine, you can make it alike to the original, or follow your path, I don't care