In 1962 Hong Kong, neighbors Su Li-zhen (Mrs. Chan) and Chow Mo-wan (Mr. Chow) discover their spouses are having an affair. As they spend time together, they develop feelings for each other, but their relationship remains chaste and unspoken, reflecting societal constraints and their own moral compass.

Tennis player turned coach Tashi has taken her husband, Art, and transformed him into a world-famous Grand Slam champion. To jolt him out of his recent losing streak, she signs him up for a "Challenger" event — close to the lowest level of pro tournament — where he finds himself standing across the net from his former best friend and Tashi's former boyfriend.