WALKING RED FLAGS A night of mind-numbing ecstasy... Eunsung had such a night seven years ago with a stranger she never saw again. Worse, she hasn't climaxed even one time since! Night after night, partner after partner, she quests for the elusive "O." Meanwhile, her two roommates, Minsuh and Okjae, confess to not experiencing that kind of pleasure at all. But after encounters with a creepy stalker and a two-timing boyfriend, will the friends realize that maybe the search for Mr. O won't be as fun as it seems?