Formula 17 is a 2004 film which was directed by Chen Yin-jung. It stars Tony Yang, Duncan, King Chin, Dada Ji, Jimmy Yang, and Jason Chang. It is a gay romantic comedy film about Chou T'ien-Tsai, a romantic Taiwanese male who takes a trip to visit an online boyfriend in person for the first time. Finding his internet relationship unsuitable for his real life, he moves on with his life and rooms with an old time friend of his. The film describes T'ien's experiences with his loyal roommate and his friends, and a surprising relationship that he develops with the local "Playboy".
Naive countryman Chou T'ien-Tsai goes to Taipei to meet an internet friend face-to-face. Being a romantic, and believing in 'true love' (he even has a book called Love Is A Kind Of Faith), he is sorely disappointed when his friend suggests they have sex with no love. T'ien instead goes to a bar and runs into his ex-classmate Yu, and in the process meets the 'Number One Playboy' Bai Tie Nan, who is notorious for one night stands. T'ien very quickly develops a liking towards Bai.
After the night at the bar and becoming roommates with Yu, T'ien gets a job as a pool attendant and has several run-ins with Bai, who seems to like T'ien mutually. Scenes with Bai and his psychologist show that Bai has a problem kissing people. After being advised to practice kissing a mirror and then a dummy, both of which fail to help him, he tries to kiss his longtime friend, but can't bring himself to do it.
One night, T'ien shows up at Bai's doorstep and they end up having sex consensually. True to his nature, Bai disappears the next day, leaving his friend to turn up at his house and explain that 'he hopes you don't misunderstand'. T'ien, hurt and unknowing of the entire story behind Bai's intimacy issues, leaves a message saying that 'this kind of misunderstanding won't happen again'.
T'ien prepares to leave his roommate's dwelling and return to his own home. In the meantime, T'ien's friends corner Bai, who admits that he hurt the person he loves. After a silent prayer for a second chance, he sees T'ien heading up an escalator. His first attempt to apologise fails, and T'ien literally runs away. He nearly gets run down by a scooter, but Bai saves him and they make up.