Introduction To The Theory Of Love summary:

Doyun followed his high school crush Hosu to university! Hosu gets drunk at the welcoming party, and Doyun tries to help him get home, but Hosu's so drunk they end up having to stay at a Motel. Doyun picks up a condom he randomly found, but Hosu just so happens to wake up at that moment...! Will Doyun be able to confess to Hosu despite his shyness?