The Unforgettable Echo

This is a story about love at first sight. It is also a story about never forgetting. They met in the most beautiful time of their youth, amazed each other's youth, and then suddenly disappeared into the vast sea of ​​people. From then on, those unforgettable times and unforgettable lovers became each other's deepest obsession. Will there really be any repercussions if I keep thinking about it?