People who have been in love more than once, people who have broken up, belong to the past; after all, they are all people we have loved - "Ex". Chen Junping (played by William Chan), who has just returned to Hong Kong from abroad, and his current girlfriend A Shi (played by Shi Ya), met his ex-girlfriend Zhou Yi (played by Gillian Chung) at the airport. Zhou Yi and travel writer A Shu (played by Chow Chung) were preparing to set off for a long-distance trip, but they had an argument and broke up. Zhou Yi, who was determined to resign and give up her apartment for this trip, was temporarily homeless and was taken in by Chen Junping and his girlfriend A Shi who were obsessed with her. Zhou Yi went to their new home to stay temporarily and found that Chen Junping, who was pursuing a material life, was no longer the Chen Junping who once had dreams and went through hardships together. The only thing that remained unchanged was that Chen Junping still missed Zhou Yi, his ex-girlfriend who had been on and off and entangled for many years, and he never let it go. In just two days, Zhou Yi recalls her past love affairs everywhere in the new home. In 30 hours, she reviews her love journey over the past six years. After breaking up with Chen Junping, she meets a doctor (played by Chapman To) who treats her broken heart. She also falls in love with the exciting and romantic gangster Ah Sheng (played by Louis Koo). Some people stay in her life for only a short time but are unforgettable, while some people stay by her side without her noticing. For example, Ah Su (played by Derek Tsang), Chen Junping's best friend, witnessed Zhou Yi and Chen Junping's reunion and breakup several times, and just silently guarded the two as a friend. Every breakup is an opportunity to meet the next one, and every wrong combination makes everyone become an "ex". However, Zhou Yi and Chen Junping are in the same room again. They are fighting but have a tacit understanding. They are close but keep their distance. Evidence of their love emerges one by one, and the longing accumulated over the years suddenly bursts out...