Both United and American Airlines have round trip airfares travelling from Denver (DEN) to Hong Kong (HKG) for $665-$670, making 1 stop. Most of the availability is on United.
Departs DENVER: Mon, Tue, Wed, Thurs from Sept 3 thru Oct 31
Returns: wide and good availability returns Mon, Tue, Wed, Thurs thru Nov 22
Enter travel information into Skyscanner [skyscanner.com]
to see what comes up, and then select your favorite OTA to book.
Hong Kong Travel Guide [discoverhongkong.com]