Only twenty-nine, Eunseong has been given a death sentence. The hospital gives her a timeline of six months. A life with an expiration date set for autumn, but instead of undergoing chemotherapy, she decides to put her affairs in order. She quits her job, moves out of her home, and dyes her hair. After a life under the strict control of her mother, timid, boring, and cautious, Eunseong impulsively chooses to break free. And while she's at it, she decides to do one more thing. Spend the night with a man she doesn't know. The man prefers light relationships with no strings attached. Despite seeing countless women, he's never been in love. Physical intimacy, that’s all he ever wanted. He’s exactly the kind of man Eunseong needs right now. She decides to spend the rest of the season by his side. Before autumn comes, we—no, I—will come to an end.