First, I just have to let you know that the music in PNB is excellent. It really helped make this drama. The story isn't anything new or different, but it is completely interesting to follow the lives of these boys/men. I commend the director for the ability to balance four stories without leaving the viewer confused or wanting more of any thing. There is great flow and character development. The actors and chemistry are what makes this drama fun to watch. Oh Jung Se portrays a mature yet still naive Gu Kwang Sul. For all his success in life he is still lacking in love until he finds the beautiful Ju Da In played by Yu Da In. They aren't my favorite couple but I definitely enjoyed their story line. Kim Young Kwang is mistaken player Kang Jin Gu. Poor guy has already grown as a person when we meet him, but the director shows us what he grew from with flashbacks to how he was. I loved to watch his interaction with his love interest Ma Se Young played by Kyung Soo Jin. They are my favorite couple. Next we have teenager Kang Min Gu played by Yook Sung Jae. Surprise...he can act. I know some people don't like idols turned actors, but I think they will make an exception when watching Sung Jae as he chases his lady love, Su Ah played by Park Cho Rong. Last but not least is the cutie Choi Ro Woon as Kang Dong Gu. He is so adorable and he has two love lines...one with his mom and one with tiny cute actress Lee Chae Mi. They are so adorable and bring a light hearted feel to the drama. I enjoyed them all immensely. I think each viewer will end up picking a favorite. Again, the music is top notch. I may rewatch this at some point. This is an easy to watch romance. I recommend it to everyone.