Link to TVB site for DIF4 Sunny is the head of a police group and he was a pretty smart head. Louis didn't get along with the other group members at first but after he knew them better, he became friend with them, especially with Sunny. Since Louis's girlfriend disappears for some years, he didn't start a new relationship because he still loves her very much. That is why when Jessica admits her love toward him, he didn't accept her love at first. He did accept her love at the end but he still loves his ex-girlfriend very much. Sunny already has a girlfriend, Charmine, but they broke up when they are about to get marry. Lee San San has always admired Sunny but since she and Charmine are best friends, she hides her love for him. They did go out after Sunny broke up with Charmine and they decided to get marry. Sunny has two sisters (Maggie) and they look exactly alike. The old Maggie is a famous writer but her family thinks she has some mental problem, which she doesn't have. Sunny doesn't know he has another sister but on his wedding day, Maggie (the young twin) killed LSS because she has some mental problem... Click on pictures to view actual sizes! Special thank you to Tina for her pictures! Even though this is a police series, I think it focuses on love relationships more than the cases. I didn't enjoy the series because I don't like the plot. I think the supporting casts did way better than the main leading artistes. I still like DIF1 and 2 better and I think DIF only belongs to Michael Tao, Kenix Kwok, and Leung Wing Chrun. I know keeping the same name can sell but since it has different casts, why keep the same name? Since Maggie acted two roles (the identical twins), it is a good challenge for her. But with her short screen time, her role is not that develop. Don't fancy this series at all. * These are only based on my opinion, not on real rating for the series! The more stars mean the better. Five stars are the maximum!