Episode 6 of "Friendly Rivalry" kicks off with a nostalgic flashback, depicting Je-yi surreptitiously slipping into her father's office, her eyes scanning eagerly for something specific. After a meticulous search, she unearths a crucial document linking Seul-gi to her father, promptly snapping photographs of it for safekeeping. However, in the contemporary timeline, Je-yi remains tight-lipped when Seul-gi inquisitively probes into what she knows, choosing to harbor the information closely.
In an unexpected twist, Seul-gi brazenly confesses to being the one who dispersed copies of her essay among the entire class, a gesture that underscores her unwavering acceptance of her past.
During a gathering for class representatives, Seul-gi accompanies Choi Gyeong, who drops a bombshell—revealing an ongoing lawsuit accusing Je-yi's father's clinic of medical negligence. Choi Gyeong hypothesizes that Je-yi's sudden fascination with Seul-gi could be a strategic maneuver to facilitate the resolution of the case.
Upon returning home, Seul-gi delves into her stepmother's possessions and unearths the case file, accompanied by documents pertaining to her father's insurance settlement. During dinner, the impulse to confront her stepmother about the murky circumstances surrounding her father's demise almost overcomes her, but she instead requests permission to remain under the same roof until her college entrance exams.
As midterm exams loom on the horizon, Seul-gi's anxiety about falling behind intensifies, especially considering her lack of access to costly tutoring materials. Struggling to maintain focus for extended periods, she endeavors to obtain a prescription for her usual medication but encounters a wall of reluctance from physicians.
Drained and desperate, Seul-gi stumbles upon an SNS account that deals illicitly in the very drug she seeks. They prompt her for a code, and upon witnessing their profile picture featuring paper birds, a memory resurfaces—she had received one from a classmate. Unfolding it, she discovers the code nestled within.
Meanwhile, Ye-ri is depicted sneaking into a hostess bar, her hidden endeavor to fund her college tuition becoming evident. As the episode edges towards its thrilling climax, an unsettling revelation unfolds: Je-yi is the mastermind behind the clandestine drug operation. She slips pills from her father's stash and personally conveys a narcotic to Seul-gi at their designated rendezvous. However, Seul-gi catches her red-handed in the midst of this illicit transaction. Je-yi, caught off guard, justifies her action by claiming that the drug Seul-gi originally sought was unobtainable and offers a more potent, efficient alternative instead. Seul-gi hesitates, troubled by the potential adverse effects lurking in the shadows.
To push Seul-gi over the edge, Je-yi produces a cram school textbook and strikes a deal—if Seul-gi can outperform her in the impending exams, she will finally unveil the mystery behind how she obtained Seul-gi's personal information. Under intense pressure and driven to desperation, Seul-gi caves in and ingests the drug, bringing the episode to a dramatic and tense conclusion.
