In chapter 29 you can go read on ridibooks it gives you 2 free rental chapters of your choosing
Daewoo figures out that theres something weird going on because thr "hajoon" hes with said that he'll be working a lot during summer break but before that they already planned a trip to jeju Island and were gonna go so Danwoo is sensing that something is not right it could be twin it could be the ml is crazy

I saw a spoiler somewhere there no twin, ml is just crazy. Now, everyone saying there's twin?