Almost everything is good. However in Asian way we have an idiom, "The window has ears, the door has eyes" That means secret must not be revealed in public, but all characters in this series always speak very loudly or shout in public. For example;
Tan Xiao Jun always shout Xia Xiang's name loudly in public, even if she knew her friend is under cover as Xia Liang Chen.
Qu Man Ting talked to Xua Xiang about Jin Xian Rong's secret loudly in front of the dorm, when she just walked in.
This is unreasonable and stupid.
Anyway except that, this series is quite excellent. There're a lot of old buildings, old cars, steam locomotives, which are quite good. The plot is good too.