First of all, I would like to refer to the movie name, serendipity. It's interesting and strange a word for me because I have never heard it before. As explained in cambridge dictionary, serendipity means the fact of finding interesting or valuable things by chance. To give you one small example, when Newton was sitting under an apple tree, an apple fell on his head. Then he discovered gravity. It was serendipity. I hope you understand the meaning. Anyway, let's write about the plot of the movie.
It is days before Christmas, and everyone buys presents for their family and girlfriend or boyfriend. In a department store, by a man and a woman accidentally choose a same pair of gloves, the first scene begins. Both of them believe fate especially the woman extremely does, and they think this coincidence is fate. Two predestinarians are not sure about it so they decide to prove this serendipity is destiny and comes up with an idea. "If this coincidence is a fate, they will surely see each other in the future," they said. The woman buys a book straight away and writes her fullname and address on its very first page and at the same time the man writes the same things on a five dollar. They can't each other since that and after years, both of them are going to get married with someone. But mysterious things begin soon coming up to them. Almost day before the man's wedding, both of them find the book and the five dollar, on which they wrote their some information. Finally, they found each other. That's it. Very shortly and understandable explanation.