Sohyun is a homeschooled introvert with an imaginary friend she talks to quite often in public. The imaginary friend, named Haein, is actually a ghost who died in her apartment complex.  He and Sohyun have been friends for some time now and wherever she goes, he goes. One day, Sohyun gets an invite to the Affinity Club, an after-school program that helps people with their social skills lead by President JB, an over enthusiastic kid always willing to help someone out. Sohyun is challenged by the affection, the taunting and the isolation from the other members that she is deemed worthy of having a true friend and being a friend.   

TL;DR

Basically, Sohyun gets another Harem