Woohyun is a policeman. Sunggyu is a Mob Boss.   And I really don’t want to spoil the rest for you.      

Sunggyu wakes up in an alternate universe where everything is beautiful and peaceful. He can't stay, not even when he finds love there. Sungyeol accidentally ends up in what can only be Hell on Earth. Yet, he finds someone who makes him want to stay there forever.  

"Anyways, here's the case. Sungyeol is invited to this wedding and his ex will be there, so I suggested he takes a fake wedding date to make him jealous," Sungjong summarises the whole plan for them, "So, any volunteers?" Myungsoo sure enough did not volunteer, but he ends up as the victim nevertheless.     (This was not a Myungyeol story, but now it is )