He is charming, ironic, nostalgic.
She is full of life, smart, passionate, she lives in the moment.
When they meet, they fall in love instantly. Later on, as they grew up next to each other, their personalities have evolved: while He is getting light hearted, She is the one starting to feel melancholic.
Thus, as the love story will be told from two different perspectives, his and hers, reflecting the moods and their inner changes, we will be confronted to the fact that there might be as many love stories as there are points of view.