In 1945, Harbin has come under the rule of Japan's puppet state known as Manchukuo. Communist agent Song Zhuo Wen successfully infiltrates Harbin Secret Service where Guan Xue holds a post as the chief of special police.
In an aerospace city in the north, seven children who were born an only child became closer than siblings and called themselves "The Big Dipper." They all promised to conquer the college entrance examinations so they can go to Beijing together but seventeen came and went and only Huang Yingzi made it. "The Big Dipper" was no more as everyone parted ways. Huang Yingzi went to Beijing for school and Jiang Yi left for the States. "Who do you like at the age of seventeen" has become a mystery lingering in the hearts of the seven people. As newcomers in the workplace, they were bruised and battered from the skirmishes between their ideals and reality. Their once pure emotions are like shining stars in the night sky. Huang Yingzi wants to reunite the group only to realize that there a question remains. Meanwhile, Jiang Yi and the others have already been presented their answer.