Mr. Heart

Jin Won is insulted when his coach assigns him a freshman student to be his pacemaker during training and his upcoming marathon. However, after testing Sang Ha, Jin Won sees his skill and potential.

After accidentally falling asleep next to Sang Ha, Jin Won sleeps more soundly than he has in years, preparing him well for the next day's marathon. After the race, Jin Won is surprised to see that Sang Ha didn't join the rest of the athletes at the celebration party.

Jin Won questions Sang Ha about why his passcode to his door is the same as his passcode. Sang Ha reveals that he went to high school with Jin Won.

Sang Ha invites Jin Won on his milk delivery run to train together.

Coach Bong takes the training team on an excursion to prepare for their competition. Sang Ha receives a threat from those whom he owes money to.

Jin Won thinks of a way to help Sang Ha with his financial troubles, while still protecting his pride.

Sang Ha's lenders pressure him into a challenging feat of finishing the marathon in order to repay his debt.

What do marathons and love have in common? They can't stop once they start.