Episode 7 of *Queen Mantis* opens with the bombshell revelation that Jung-yeon is pregnant. Seeking solace, she takes refuge at A-ra's place, attempting to grapple with the seismic shift in her life. However, their tranquil moment is interrupted when Su-yeol offers them a ride to Min-jae’s funeral. At the somber event, Min-jae’s father creates a scene, and Su-yeol, feeling a sense of fraternal duty, steps up as the chief mourner, embodying the role of an elder brother.
Later, amidst the melancholy, Su-yeol opens up to Jung-yeon about a poignant memory—a beach picnic he once shared with I-shin and Min-jae. He confides in her about his struggles with identity and blood ties, revealing that he became a police officer to prove he was nothing like I-shin. Now, with the case that once defined him resolved, he feels adrift and lost. Jung-yeon, with her usual warmth, comforts him, and they mend the rift that had briefly formed between them. Meanwhile, A-ra, who harbors an aversion to dogs, musters her playful side to uplift Su-yeol’s spirits.
The plot thickens when a new copycat murder surfaces, this time targeting a doctor, though the execution is far from flawless. Jeong-ho, eager to have Su-yeol back on the team, enlists even Jung-yeon’s help to persuade him. In the interim, Jung-yeon continues to stay at A-ra’s, where she finally divulges her pregnancy. She vows to shower Su-yeol with love, even if he doubts he deserves it. A-ra, in a moment of candidness, admits to feeling a twinge of jealousy.
With Su-yeol away, I-shin reneges on a previous agreement, much to Na-hee’s frustration. Undeterred, Na-hee provokes the elusive killer, refusing to believe that I-shin genuinely cares for her son. I-shin, ever the strategist, turns the tables, bringing up the looming custody battle. She accuses Na-hee of pushing her son away so he would choose his father—a move Na-hee sees as the lesser evil, even if it meant hurting her child. Na-hee, incensed by the comparison, retorts that I-shin is not helping her son but using him as a pawn. I-shin laughs it off, but when alone, her façade cracks, revealing a hint of vulnerability.
Upon Su-yeol’s return, he is met with a cold reception from the unit. However, Na-hee, recognizing the urgency of the situation, extends an olive branch, emphasizing the need to halt the killer’s reign of terror. Seeing her son safe and sound, I-shin re-engages, accepting a call from the copycat. The copycat, revealing herself as Yeon-joong, is met with I-shin’s trademark mockery. Enraged, Yeon-joong unleashes a tirade, claiming she killed Min-jae to shield I-shin and her son’s identities. She boasts that Su-yeol can now live happily ever after, thanks to her intervention.
In that pivotal moment, both Su-yeol and I-shin experience a flash of realization—the copycat is none other than A-ra. She had been present when Min-jae taunted Su-yeol and Jung-yeon, and it was A-ra who had introduced Jung-yeon to Su-yeol in the first place. The pieces of the puzzle finally fall into place, revealing a sinister twist in the tale.
At this very moment, as the police officers desperately attempt to establish contact with the women, A-ra deftly switches off their phones, a sly smile playing on her lips. Subsequently, she whisks Jung-yeon away on a drive. At the gas station, Jung-yeon, seizing the opportunity, turns on her phone and is jolted by the sight of Su-yeol's urgent warning messages. In a panic, she attempts to flee, but A-ra merely laughs, unperturbed.
Su-yeol, alerted to the situation, dispatches a patrol car to Jung-yeon's supposed hiding spot. Yet, A-ra, with chilling efficiency, dispatches the two officers. She then reveals her true identity, Yeon-joong, to Jung-yeon and proceeds to kidnap her. As a macabre parting gift, she informs Su-yeol of Jung-yeon's pregnancy.
The women find themselves sequestered in A-ra's childhood sanctuary. Jung-yeon, desperate to provoke a reaction, tries to goad A-ra, but the latter remains unflappable, revealing that Jung-yeon is merely a pawn in her game. In fact, she had previously introduced several other girls to Su-yeol before he finally settled on Jung-yeon. She claims her actions stem from a sense of duty, as I-shin had once looked after her.
A-ra then makes a call to I-shin, engaging in a chilling monologue about her intentions to kill Jung-yeon. I-shin, initially appearing indifferent, eventually offers herself as a substitute, a proposition A-ra readily accepts.
For once, Su-yeol finds himself torn, confessing to I-shin that A-ra intends to kill her. I-shin, with a steely resolve, points out that this is precisely what he had desired - for her to seek redemption. She cannot bear the injustice of her being tried for killing abusers while A-ra roams free, having murdered the innocent.
The unit is abuzz with speculation about Su-yeol's hesitation. Sung-gyu even goes so far as to theorize that Su-yeol, A-ra, and I-shin are colluding. Na-hee, however, rebukes him, expressing sympathy for Su-yeol and the terror he must be enduring. Yet, she too suspects that A-ra and I-shin are conspiring, using Su-yeol as a means to escape.
Commissioner Hong, wary of the risks involved, attempts to reject the proposed plan. But Jeong-ho, taking full responsibility, proceeds regardless. He informs Su-yeol of the escape theory, leaving the latter stunned. Su-yeol is equally surprised to find himself genuinely believing in I-shin's noble intentions.
Nevertheless, Hong issues special orders to Sung-gyu, Hyuk, and Na-hee. They are to eliminate A-ra and I-shin if capture proves impossible.
I-shin sets foot in Woongsan, her arrival marked by a mix of anticipation and trepidation. She reluctantly accepts the tracker, a symbol of her connection to the mission at hand, yet firmly declines the bulletproof vest. With a wry smile and a hint of dark humor, she quips that it seems everyone is eager for her demise. Su-yeol, sensing the tension, steps in with a reassuring revelation, stating unequivocally that he, for one, does not wish her harm.
Just as the atmosphere begins to thaw, A-ra's call pierces through the moment, bringing urgent instructions regarding the impending hostage exchange. With time of the essence, preparations commence. Before they embark on their perilous journey, Su-yeol, with a subtle yet meaningful gesture, cuffs I-shin's wrist. However, in a secretive act of trust, he slips the key to the cuffs into her hand, a silent promise of support and solidarity.
