As a child living in a seaside town in southern Taiwan, studious Jonathan (Ray Chang) was asked by his concerned teacher to look after rebellious classmate Shane (Joseph Chang). Ten years later, what was once a good-natured obligation has since blossomed into a warm friendship, with Jonathan still on the academic track and Shane now finding his calling on the basketball court.

Taiwan-born schoolgirl Carrie (Kate Yeung) arrives from Hong Kong to join her mother after a disagreement with her father and transfers to their school. She befriends Jonathan and convinces him to join her on a secret day-trip to Taipei and in the evening she seduces him in a sleazy hotel but Jonathan backs down clearly distraught. Eventually, her observations of his and Shane's friendship leads her to believe that he is gay and in love with his best friend.

Carrie then meets Shane through Jonathan after a school day where Shane develops an interest in Carrie. Despite her initial misgivings about the boorish Shane, she eventually gives in to the troublemaker's roguish charms. She accepts his offer to become his girlfriend on the condition that he manages to enter university.

Later, Shane pulls his act together and gets into university, while Jonathan, distracted by his burgeoning sexual identity crisis, does not. Shane does his best to keep secret his feelings for Carrie in order to protect the feelings of his lifelong friend. Despite all their best efforts to keep their personal feelings secret, the truth eventually emerges, forcing all three to view their relationships in an entirely new light.

Following a party, Shane is hit by a car while riding his motorbike. Jonathan comes in to bring him back home. There Shane suddenly initiates and they have sex to which Jonathan reluctantly gives in to him. Early next morning while Shane is still asleep, Jonathan calls Carrie to always look after Shane and then leaves.

Shortly after, Shane takes Jonathan and Carrie to the beach. Jonathan tells Shane they should stop seeing each other. Furious, Shane tackles Jonathan to the ground and asks if he really means it. Carrie leaves the two boys alone and watches from the car. Shane repeats again that best friends can tell each other anything. Jonathan says that Shane may no longer want to be friends anymore but finally confesses his romantic feelings for him and walks away. Shane then shouts that he has a secret as well and reveals that he has been diagnosed with Attention deficit hyperactivity disorder which led to loneliness in childhood and how he always knew the teacher forced Jonathan to be his friend. Johnathan's feelings are seemingly left unrequited in the end as Shane answers to his confession that he sees him as his best friend.

• Joseph Chang as Shane (余守恒)
• Ray Chang as Jonathan (康正行)
• Kate Yeung as Carrie (慧嘉)

Eternal Summer won one awards out of four nominations at the 43rd Golden Horse Awards in 2006.

• Eternal Summer at IMDb  
• Eternal Summer at AllMovie