Sayo Katagiri is a hardworking office worker who believes she can achieve anything if she puts in enough effort. Miharu Morimoto is a nurse whose hopes of getting married begin to fade after being in a relationship for far too long.
Sayo realizes that her senior, Sasayama, has been noticing how hard she works, all while she struggles to make sense of her one-night encounter with Aoki. Meanwhile, Miharu finds herself torn between Tokita, a man she met on a dating app, and Ryota, her boyfriend of six years, whom she has been living with.
Lacking confidence in herself, Miwa finds it hard to leave Shin, who tells her she’s cute and says he needs her. Meanwhile, Akane is invited to dinner by Igarashi, the head of sales at one of her company’s business partners. He makes a reservation for her at an upscale restaurant she would normally never visit.
Miharu misses the last train while on her second date with Tokita. She admits that she already has a boyfriend, but Tokita responds with heartfelt sincerity. Meanwhile, at PBS, Kobayashi explains that according to his analysis, desire tends to fade the longer a relationship lasts. Gonda and Kobayashi then debate the question, “Should I do it or not?”
Miwa runs into Shin’s girlfriend on the street, leading to a confrontation. At PBS, the discussion turns to women like Miwa who are treated as little more than someone to sleep with. Kobayashi analyzes why some women become overly devoted to the men they are involved with.
Miharu catches Ryota cheating on her. Back at home, she confronts him about what happened, but the answer he gives her is clearly a lie.
Sayo confronts Ryota about cheating. However, it turns out that the woman he was with had actually been helping him prepare to propose.
Miharu finds herself torn between Tokita and Ryota, and the situation quickly spirals into chaos. As she looks back on the time she spent with Ryota, she is overwhelmed by regret and a profound sense of loss.