Saeka is in her fourth year as a working adult and has cultivated a reputation as a dependable and responsible employee whom everyone in the office trusts. Beneath that composed exterior, however, she struggles to rely on others—even her younger boyfriend—and her only private outlet for stress is smoking cigarettes in secret. The careful balance of her daily life is disrupted when her former superior, the one person who witnessed all the mistakes she made during her rookie days, is transferred from the Kansai region to her current office. Determined not to show any weakness in front of him, Saeka does her best to maintain her polished image. Yet as they spend more time together, she finds herself gradually bonding with him, and he begins to help her relieve her stress in his own quiet, unexpected way. The story unfolds against the backdrop of a modern Japanese workplace, exploring themes of hidden vulnerability, the pressure to appear perfect, and the bittersweet, heartwarming connection that grows between two people who share a complicated past. Through late-night encounters and moments after the last train, their relationship deepens, challenging Saeka to let down her guard and accept support from someone who knows her better than she would like.