To those of you planning to buy the official English chapters, please, please take note: The story of Bae Songwoo and Kim Sangjin ends in S1 (chapter 30). Chapter 31 onwards are about some other characters that we've never seen before. So plan your purchase on whether you want to read that or not.
...I have no idea what to do with the rest of this Ink I've purchased. 45+ chapters worth of money, but no more Songwoo... :'(