Story: The drama starts off with the handler of 5 particular undercover cops to be mysteriously murdered who had their details wiped off the system to protect their identities as there are 'black cops' in the police force. Just before his death he was able to pass on the message to another with the mission to search for the 5 UCs and protect them. This drama portrays the life of being an undercover through all their sacrifices and hardships that they must endure for the sake of their work. Acting/Cast: If you were a crazy fan of CHARRAY... you would love this - their chemistry is amazing! Honestly, I never followed TVB dramas in their earlier days so the first time I saw them was in My Sister of Eternal Flower and that drama was a total flop for me. But this... this was amazing! They were amazing... I now understand why everyone was crazy about them! Adding Oscar into the picture, I actually really enjoyed the friendship of the 3 of them together - it felt really natural. The more lovey-dovey couple would be Sammy and Sharon. I loved watching Sammy in this - he was so cool especially when he was not lovesick. What really bugged me was when the drama focused on their relationship a little too much - they really had no chemistry but IMO it was probably due to Sharon, her acting really has not improved much and she seems too stiff and unnatural in their scenes together (thinks back to The Ultimate Addiction - shudders!) Another that surprised me was Benz! I am so used to seeing him in more simple and comedic roles and his character here was great - he does that evil smile really well that you really can't tell what he's thinking... you are kinda left thinking is he good or is he bad? We actually don't know until the VERY end. Michael and Elena also deserves a mention - as they are veterans they were pretty much perfect in their roles. Music: Again, I'm not too familiar with HK music, but I really liked the choices in songs for this, as well as the background music. Everything was really fitting. Rewatch Value: Hmm.. there really is no point rewatching this as all the suspense is gone now since I know what happens. There will no longer be the feeling of wanting to know whats gonna happen next.. no more guessing who the undercovers could be.. no more guessing who is good and who is bad... no more of that.. BUT I will definitely sit through this again especially for the charray moments! Overall: This drama was brilliantly written with a solid plot which was played out nicely. I loved how they consistently kept the suspense throughout with a handful of comedic and dramatic moments thrown in here and there. Props to Charmaine and Raymond! If you love this genre of dramas, I highly recommend this one! It will definitely keep you on edge, but be sure to have a tissue box nearby as they will be needed - nah not really.. but it definitely goes darker and heavier towards the later episodes. I believe this was one of the best - maybe even the best TVB drama I have seen.. HIGHLY RECOMMEND!