The main drama poster says the following:
From a teenager to a thirty year old adult man in an instant, the story of a young mans maturity into an adult. Experiencing a perfect fiancee turning into a teenage boy in an instant, the story of a young womans confusion.
So the character chart makes it clear once and for all that Kang Kyung Joon is the main character, but well be seeing him in the body of Yoon Jae. It also makes it clear who the supposed OTP is, what with the matching blue and pink lace cute frames around Kyung Joon and Da Rans pictures, whereas Yoon Jae, Se Young, and Mari get regular frames. But one thing I got wrong was Da Rans age shes twenty six, which means shes eight years older than Kyung Joon. Since I was totally beyond fine with the age difference between the OTP in SMM (10 years), it doesnt bother me here either. Heres what the major character links say.
Da Ran Kyung Joon: A two-arrow line between them that says Teacher-student, love!?
Da Ran Yoon Jae: A two-arrow line between them that says Engaged
Da Ran Se Young: A two-arrow line between them that says Love rivals
Kyung Joon Mari: A one-arrow line from Mari to Kyung Joon that says Good friends, In love with
Choong Shik Mari: A one-arrow line from Choong Shik to Mari that says In love with | 
มีใครอยากส่อง big กับเราไหมค่ะ
