Love Countdown (Cashier Meong)

"You're going to fall to your death?"
"Huh?"
"I'd prefer you to live if possible. Because if you die, I'll die too."

Seo Hae-Won met a man on a bridge while drunk. He thought they'd accidentally spent a night together, but he told him he'd known Ji-Hun for a very long time. And that's all? At the edge of a cliff in his life, which had seemed so bleak, he nonchalantly reached out.

"What I want isn't your gratitude, Ji-Hun."
"So... are you saying we should date?"
"Dating won't do. That won't satisfy me. Love me. Just like I love you, Ji-Hun."

Hae-Won, seemingly stunned by the passionate confession of love from a stranger, simply added refreshingly.

"Shall we break it down into five stages?"
"... Stages?"
"Stage one is sex, stage two is kissing."

He'd already had sex and kissed. So what are the remaining stages three, four, and five? And, who on earth is that man in Seo Hae-Won?

(Source: Ridibooks, translated)