Episode 4 of "Our Unwritten Seoul" kicks off with Ho-su storming out of his company, his abrupt departure leaving his boss Chung-ku incensed and vowing revenge, promising to complicate Ho-su's path to new employment. Meanwhile, Mi-ji encounters Ho-su unexpectedly at the abode of Ro-sa, the charming restaurateur, where she is startled to learn of his resignation.
Back at her office, Mi-ji finds herself ensnared in a precarious situation. The director, with a calculating gleam in his eye, saddles her with the responsibility of overseeing a pivotal meeting, a setup that subtly positions her as the scapegoat in case of failure.
Later, Mi-ji ventures to visit Ho-su, who is grappling with the aftermath of his resignation. Feeling abandoned by all, he appears adrift and desolate until Mi-ji offers a beacon of hope, suggesting he turn to crocheting as a therapeutic outlet to redirect his thoughts towards something constructive.
The subsequent day, Ho-su bombshells his mother with the startling revelation of his joblessness. Later, he reconvenes with Mi-ji at a bustling shop, accompanied by Ro-sa, where an astonishing twist is unveiled: Ho-su has assumed the role of Ro-sa's legal representative. With a nudge of encouragement, Ro-sa entrusts Mi-ji to facilitate future engagements through Ho-su, thus setting the stage for a new chapter in their intertwined lives.
On their journey back home, Mi-ji's ears catch snippets of Ji-yun's conversation, revealing that she hadn't intended to include Mi-rae—whom Mi-ji continues to pose as—in the class reunion. Mi-ji, feeling the sting of exclusion, declares with determination that she and Ho-su will certainly be present.
Elsewhere, Mi-rae acknowledges the need to give their grandmother a haircut, a task once joyfully undertaken by Mi-ji. Meanwhile, their mother stumbles upon unpaid hospital bills, sparking a wave of anxiety as she fears that Mi-rae might be hiding something, further exacerbating their financial woes.
At the reunion, Mi-ji's former classmates express pity towards Mi-rae for her civil service exam failure and ridicule Mi-ji for her role as a janitor. Stunned into silence, Mi-ji remains tight-lipped until Ho-su intervenes, fiercely defending her honor. Afterwards, he gently questions her silence, wondering why she didn't speak up for herself.
Later in the evening, Mi-ji receives a call from Mi-rae, urging her to return home to give their grandmother a haircut, as their mother will be out with friends. However, the request clashes with a rescheduled meeting. When Mi-ji declines, Mi-rae responds by demanding that she settle the hospital bills from her own funds.
The following day, Mi-rae finds herself receiving crates of strawberries from Se-jin, which trigger reflections on her solitude, realizing she has no one to share this sweet gesture with. She also acknowledges the harsh self-criticism she often indulges in. Seeking solace, she decides to make strawberry jam with Ho-su's mother, who warmly commends Mi-rae's inherent kindness and resilience.
On the fateful day of their scheduled meeting, neither Mi-ji nor Ho-su could establish contact with Ro-sa. A wave of anxiety washed over Mi-ji, prompting her to hastily make her way to Ro-sa's residence. Upon arrival, her heart sank as she discovered Ro-sa lying helplessly on the floor, a victim of an unforeseen fall. However, instead of rushing to her aid, Mi-ji found herself paralyzed by a sudden panic attack.
A series of haunting flashbacks unfolded, revealing Mi-ji's troubled past. Years ago, following a devastating injury, she retreated into the confines of her room for an extended period of three years. During this isolating time, her sister Mi-rae stepped into her shoes, even cutting her own hair short to impersonate Mi-ji and ensure her graduation. This was the reason Mi-rae, and not Mi-ji, occupied the graduation photograph alongside Ho-su. It wasn't until their grandmother suffered a critical collapse that Mi-ji was compelled to emerge from her self-imposed exile.
Switching back to the present, Ho-su's timely arrival brought a semblance of relief, as he swiftly came to the aid of both Mi-ji and the fallen Ro-sa. At the hospital, Ro-sa was admitted for treatment, and the eagerly anticipated meeting was inevitably postponed until her recovery.
Later, consumed by guilt, Mi-ji blamed herself for her grandmother's stroke. Ho-su, with a tender yet firm tone, refuted her self-recrimination, sharing his own heart-wrenching story: he had lost his father in the very same accident that had robbed him of his hearing. Still masquerading as Mi-rae, Mi-ji inquired about the source of his protective nature towards her. In a moment brimming with raw emotion, Ho-su finally confessed his feelings: Mi-ji had always been his first love, and his affection for her remained steadfast. The episode concluded on this poignant and heartfelt note.
