Episode 11 of "Friendly Rivalry" unfolds with a chilling glimpse into Tae-jun's haunting past. From his tender years, Tae-jun harbored an obsession with dissecting living creatures, fueled by an unquenchable thirst to uncover their hearts. This macabre fascination propelled him towards a career as a surgeon, where he convinced himself of his uniqueness among mankind. Yet, his perception shattered when he witnessed Je-yi displaying similar tendencies. Believing them both to be "chosen ones," Tae-jun forged an unsettling connection with his daughter.
In the present, Je-yi narrowly rescues Seul-gi, but their relief is short-lived as they realize Je-na has vanished. Scrambling to track her whereabouts, Je-yi dashes to Je-na’s house and discovers her phone abandoned on a desk, a chilling omen of her sister's plight.
The following day, a scandal rocks the school as a video of Na-ri indulging in drugs circulates among students. Meanwhile, detectives arrive with a pivotal CCTV footage, seeking assistance in identifying a suspect. To everyone's astonishment, Je-yi steps forward, naming her sister Je-na as the culprit behind the drug incident. However, her true intention lies in leveraging the police to expedite Je-na’s location.
Determined to unearth the truth, Je-yi and Seul-gi delve into CCTV footage from the day Je-na entered the school. Their investigation leads them to a startling discovery—Choi Gyeong had encountered Je-na that very day. Trailing Choi Gyeong, they uncover her near Seul-gi’s house, where she has been surreptitiously informing Seul-gi’s stepmother about her father’s murder.
At this crucial juncture, Je-yi receives a cryptic phone call. The caller, cloaked in mystery, claims knowledge of Je-na's whereabouts and demands 30 pills in exchange for this vital information. With her options dwindling, Je-yi, Seul-gi, and Choi Gyeong don disguises and venture to the designated bar. They hatch a plan—concealing the pills within the men’s restroom and stakeout from afar.
While Seul-gi and Je-yi shadow a suspicious figure, Choi Gyeong edges towards the restroom. The episode culminates in a breathtaking twist—Je-yi and Seul-gi unexpectedly encounter Byeong-jin, while Choi Gyeong stumbles upon the startling revelation that the enigmatic caller was none other than Ye-ri, casting a shadow of doubt and intrigue over their quest.
