The Film An Autumn’s Tale is a romantic comedy where it showcases the cultural shocks a Hong Kong woman experienced when residing in NYC.
The film begins with a woman from Hong Kong packing up to go to NYC, with her mind set on meeting her boyfriend that she didn't see for a few years. Her image of their reunion, of course, is quite rosy, only to have her expectations ruined a day after she arrived to NYC when she realized that her boyfriend (now not) had a new girl friend. Thus, this set the wheels in motion for the cousin (whom she was going to live with) to spark a romantic relationship with her.
At first, the woman had a negative image of her cousin; After all, on the first day she met him, he was a rowdy guy pushing through the police, was noisy, had a somewhat broken, rusty car, and went on a street race on the way home. Furthermore, the place he lives is in a bad part of NYC; Loud, overnight parties, dirty, etc. But the women likely started seeing the cousin in better eyes when he helped her decorate her room.
Later, she went got a babysitting job and a job as waitress in a restaurant, both under the same family. The husband however started having interest in her, and to protect her, the cousin and his crew beat the “dirty old man” up.
I think the main point the began to start turning the relationship between the cousin and woman into a romantic one was when they went to the beach. The cousin mentioned how he wanted to open a new restaurant facing the Atlantic Ocean. However when he couldn't come up with a good name, the woman came up with the name Sampan. Afterward, they implicitly agreed to run the restaurant together, which to me, sounds like they hinted interest in becoming boyfriend/girlfriend, and perhaps later, husband/wife.
After this incident, the cousin decided to start a party. At first, I thought he did it because it was the woman’s birthday on the day of the party, but then a scene came up where the woman goes into the guys room, and realizes that his birthday is on the day of the party. I am still unsure of the reasoning behind the party. This party was important because it started the (temporary) separation between the two.
Of course, since this is a hollywood-like film, the two re-met at the same place the cousin decided to start up his restaurant, while the cousin was handling business in the restaurant. After that, they probably lived happily ever after.