Leaning on each other through thick and thin, a trio of best friends stand together as they experience life, love and loss on the brink of turning 40.

Ai studied abroad until, after being expelled for quarrelling, his father forces him to return to Thailand where he attends classes at the university where he teaches. There, Ai meets Chen Nhai, his new Harley Davidson-riding classmate who has an obsession with a yellow duck keychain. Ai falls in love at first sight and a whirlwind romance ensues.

Taira Kei has a talent for contemporary dance since he was young and went to study in Germany to join a dance company in his teens. He has won several international competitions and was referred to as a “prodigy”. However, he encountered a setback in the middle and got frustrated. He returned to Tokyo and takes a part-time work while he tries to re-capture his dream.

Nishihara Yui is a Chemisty teacher in her 30s, working at a prestigious high school. Even while continuing a love affair with a married colleague, she was still lonely until she meets Kei and gets swallowed in passion.

Cher is a gamer who wants to make it big in the e-sports industry. However, his plans are dramatically altered when he's made to intern at a company. There, his boss Gun has him do some pretty weird errands, confusing Cher about his true intentions. What do Gun's actions mean? And will Cher return back to his gaming life?