德士当家讲述了在新加坡都市中出租车司机的故事，故事创作灵感与概念，改编自畅销小说《德士司机的日记》里头主人翁的真实故事。葛米星饰演的蔡博士被解雇后找不到工作，自杀未遂，结识了李国煌饰演的的德士司机“阿头”，走投无路的情况下博士做起了德士司机，但也因羞愧于从事这份工作而不敢告诉家人。两人也从不合，转到在生活与个人难题上互相扶持，由冤家变“麻吉”！蔡博士也通过德士司机这份工作重新认识了生活的真谛。

"Taxi! Taxi!" is a social comedy set in the metropolitan city-state of Singapore, told through the encounters of two characters who are in what is widely perceived as the most sociable profession on the island taxi drivers. Inspired by famed blogger Dr Cai Mingjie's real life accounts as a taxi driver in his bestseller "Diary Of A Taxi Driver: True Stories From Singapore's Most Educated Cabdriver", the movie follows the trials and tribulations of a retrenched microbiology scientist, Professor Chua, as he turns to taxi driving after several failed job attempts. Along the way, he befriends (although they didn't quite start off as friends from the get-go) a veteran taxi driver, Ah Tau. The two men, who appear to be polar opposites of each other in every aspect from educational levels, personalities, attitudes toward life and even the languages that they speak, eventually find themselves interdependent and influencing each other in ways that they probably had never imagined