Episode 6 of Surely Tomorrow opens with an awkward car ride home, as Kyeong-do and Ji-woo sit in silence, reflecting on their time at the amusement park. Finally, Ji-woo breaks the silence, telling Kyeong-do that she had a good time. Outside her house, she invites him to join her for a meal. They order food and watch a movie together, with Kyeong-do falling asleep on the couch while Ji-woo continues to watch.
The next morning, Ji-woo watches Kyeong-do sleep and gently reminds him about work as soon as he wakes up. She tells him to go shower while she washes, dries, and irons his clothes. Kyeong-do is embarrassed to step out of the bathroom wrapped in a towel to collect his clothes, but Ji-woo deliberately teases him.
At work, Han-kyung comments on Kyeong-do's outfit. He lies, but she remains upset about his decision and wonders if he's refusing to go to Chicago because of Ji-woo. She tells him to stop ruining his career and future for someone who clearly does not care about or love him.
Meanwhile, Jin-eon meets Min-woo to discuss his exposé article that led to his divorce. He tells Min-woo that Ji-woo is living with her ex, Kyeong-do, and reveals that Da-hye has been calling him, asking him to convince Min-woo to speak to her.
That night, Kyeong-do lies awake in his apartment, thinking about Han-kyung's words. He receives a text from Ji-yeon asking to meet the next day. However, the following afternoon, Ji-yeon is having lunch in a cafeteria without any memory of arranging the meeting.
Kyeong-do finds her, stops her from overeating, calms her down, and takes her back to the office. Once there, Ji-yeon regains her memories and asks for a change of clothes. As instructed, Secretary Yoo laces Ji-yeon's coffee with drugs and serves it to her, alarming Kyeong-do.
Ji-yeon talks about Ji-woo and the company, wondering if Ji-woo will change her mind. She reveals that Min-woo has already searched for a nursing home for her future care and admits that she was the one who convinced Ji-woo to break up with Kyeong-do in 2015.
Later in the evening, Kyeong-do and Ji-woo sat down to a luxurious dinner at a refined restaurant. As he thanked her for treating him, he casually referred to her as a friend, an unexpected remark that subtly disturbed her. She asked him to call her his female friend instead, hinting at the possibility of being his girlfriend, and they both laughed it off.
Kyeong-do inquired about the reason behind her leaving him the second time. Ji-woo didn't answer directly but later revealed how Jin-eon once compared her to Cinderella. She said she saw herself in the same light, a lonely princess without family or friends, waiting for her Prince.
The story shifts back to 2017 when Ji-woo and Kyeong-do were spending time together at a park. Kyeong-do received news of his father's car accident. Ji-woo waited alone at his apartment, checking on him while he supported his mother. When he returned, he told her that his father was still recovering.
Ji-woo refused to stay with Se-young and vowed to wait for him. Later, Ji-yeon found Ji-woo outside the apartment and revealed the truth about their mother's affair. Ji-woo finally understood why her mother resented her and wondered if Ji-yeon would now see her differently.
Ji-yeon recalled hiding the truth from her since she was seven and begged Ji-woo to leave the country to protect Kyeong-do from their mother's cruelty. She asked Ji-woo to let him focus on his parents, who needed him more than she did. Ji-woo visited the hospital, witnessed Han-soo's deteriorating condition, and ultimately left for the US.
When Kyeong-do returned after his father's recovery, he was devastated to find the apartment empty and couldn't locate Ji-woo anywhere.
Back in the present, Ji-woo apologizes to Kyeong-do for leaving him, expressing remorse for her absence during his most vulnerable moments. She scolds herself for allowing him to be walked over and blames herself for abandoning him at his lowest point. Despite everything, Kyeong-do asks if she's feeling better now, admitting that he felt inadequate and turned to alcohol because he missed her so deeply. The two finally open up, hugging and sobbing together.
On the drive home, Ji-woo ponders the pain he'll feel when she leaves again, while Kyeong-do worries about how to tell her about Ji-yeon's illness. The next morning, he plans how to break the news, but Ji-yeon calls him, followed by a text that Ji-woo notices. Confused, Ji-woo confronts him just as Ji-yeon calls her directly. Ji-woo asks Kyeong-do to prepare an explanation and leaves to meet her sister.
Ji-yeon sugarcoats the truth, claiming she forced Kyeong-do to stop Ji-woo from leaving Korea. She hides her illness and listens as Ji-woo speaks fondly about him. Ji-yeon then announces her plan to retire and asks Ji-woo to take over the company.
Back at the apartment, Kyeong-do worries that Ji-woo will push him away. Instead, she decides to accept her sister's position at Jarim Apparel. Kyeong-do is stunned that she's not upset, soon realizing she still knows nothing about Ji-yeon's condition.
That night, Doo-jin asks Kyeong-do to help Han-kyung stop drinking. Kyeong-do tells a drunk Han-kyung that he's committed to Ji-woo and asks her to let him go. The next day, Ji-yeon tells Min-woo about Ji-woo's decision, lying that Ji-woo was moved after learning about her Alzheimer's.
When Ji-yeon mentions her illness, Min-woo urges her to prioritize her health over the company. Meanwhile, Kyeong-do seeks relationship advice from a colleague. Intern Bo-ra bluntly concludes that his female friend has feelings for him.
Se-young later invites Kyeong-do over to celebrate Ji-woo's achievement. At the gathering, the friends celebrate Ji-woo until Jeong-min arrives, touched to discover they're also celebrating his birthday. Both occasions are celebrated together.
That night, Min-woo dines with ED Choi and frets over how the board will react to Ji-woo taking charge. He criticizes her competence, but ED Choi calls out his disrespect. After dinner, Min-woo orders Secretary Yoo to increase Ji-yeon's medication dosage.
Later, Kyeong-do confides in Jeong-min about his fear of confessing to Ji-woo. Jeong-min scolds him for constantly belittling himself. Kyeong-do walks Ji-woo to her car and gifts her special slippers to help with her back pain. She calls them boring but accepts them anyway.
There's awkward tension between them, but as she sets to drive off, Kyeong-do stops her and asks her to spend the night at his place. The episode ends with a flashback to the time Kyeong-do worked on the article announcing Ji-woo's marriage, breaking down in tears on the university lawn.
