There are several new things we can deduce from this trailer, that has been absent in the past promotional material.
1. There are vampires.
We start off the trailer with the introduction that vampires are among us. Hiding their true selves to blend into the general population. Queue "new girl" who is, you guessed it, a hidden vampire high school student. Baek Ma Ri (Seol Hyun) is withdrawn, quiet, and drinking blood juice boxes in the bathroom, because of her vampirism and the fear of negative reaction to her identity.
2. Our leading man Jeoong Jae Rim (and most of the class) dislike vampires.
The amount of disgust that Jae Rim says the word "vampire" at the end of the clip gives a huge hint to his inner feeling about the species. Looks like this relationship is going to turn rocky when he discovers his crushes "secret".
3. Lee Jong Hyun makes one hella-sexy vampire.
Yummy is the word that goes through my mind anytime Lee Jong Hyun (CN Blue) pops up in the trailer. The guy is super sexy and perfect playing the other hidden vampire student, Han Si Hoo.
4. Seol Hyun might actually have chemistry with her leading men.
There has been a lot of dissatisfaction with K-idol Seol Hyun landing the leading lady role. I personally have never seen her act so can't say if it will be a good fit or not but I can understand where they are coming from. The glimpses of her character have been pretty bland. HOWEVER, at least in the few seconds she was connecting with both of her costars, there seemed to be some chemistry brewing. Let's cross our fingers that this is true, and not just a pretty screencap.
Orange Marmalade Trailer