Episode 4 of "Butterfly" kicks off with a poignant flashback to David and his team's fateful last mission alongside Caddis, a chapter set nine years prior in the Philippines. Moments before disaster struck in the form of an ambush, David's instincts kicked in, prompting him to call Juno with an urgent request to place Rebecca under protective custody. The mission's aura of unease weighed heavily on him.
As the ambush unfolded, David and his compatriots fought with unwavering determination, yet despite their valor, all members perished, with David as the sole survivor. Sensing impending peril and thinking solely of his child's safety, David ingeniously feigned his own death.
Juno, bearing the heart-wrenching news, relayed it to Rebecca and her aunt. To Juno's astonishment, Rebecca's reaction was a bizarre blend of laughter and tears, a poignant contradiction of emotions.
Elsewhere, Juno Dispose of the bodies of her fallen operatives in the East Sea with solemn reverence. They presumed Gun, too, had succumbed to his wounds, only for him to miraculously regain consciousness, narrowly escaping death at the hands of one of the cleanup crew members.
In her quest to uncover Oliver's whereabouts, Juno interrogated Gun, to no avail. His ignorance on the matter left her no closer to her goal.
Concurrently, Juno's South Korean connections struggled to trace David's whereabouts, encountering obstacles not only in locating him but also in finding Eun-ju's family, adding another layer of complexity to an already tangled web of intrigue.
As the conversation veers in that direction, they clandestinely converge with David, Rebecca, Eun-ju, and Min-hee. Eun-ju's father readily agrees to assist David in securing visas, whereas her mother, filled with concern, pleads for his safe return. David further implores Eun-ju's parents to accompany them to their hideout, as he gears up to confront Caddis. Meanwhile, Juno phones David, only to leave a voicemail proposing a swap: Juno for David's family. Little does she realize, David poses as the least of her worries, with Dawson hot on her trail, determined to bring her down.
To extract information from Oliver, Rebecca adopts the guise of the stern enforcer, while David takes on the role of the benevolent intermediary during their interrogation. Leveraging AI, they orchestrate a scenario where Juno seemingly refuses to negotiate Oliver's life for David's family. David expertly manipulates Oliver, striking at his emotional vulnerabilities. In no time, Oliver is eager to confess: the murder of Jae-hun, his mother's cover-up, and the classified secrets she has been peddling to the Russians.
Having heard Oliver's confession, David concludes that they must return to Seoul. He intends to aid Dawson in gathering incriminating evidence against Juno.
On Juno's end, despair begins to set in as her team struggles to locate her son and David. They meticulously monitor all of David's past and present contacts, yet to no avail.
Before their departure for Seoul, David persuades Eun-ju to allow him to conclude his battle with Caddis. Eun-ju is apprehensive about the implications, but David reassures her that everything will be alright.
Together with Rebecca, David makes his way back to Seoul and swiftly devises a strategy to gain access to Dawson by cloning his assistant's phone and acquiring his schedule. David offers Rebecca an opportunity to withdraw before the situation escalates.
He is determined not to exploit her as a pawn, unlike what Juno had done. His intention is to rescue her, yet Rebecca is resolute in seeing their plan through to its conclusion. After all, it was Juno who had first shattered her life. Leveraging Dawson's schedule, Rebecca and David devise a clever strategy to momentarily distract his security detail. They cleverly use Dawson's meeting with Jae-hun's lawyer as a guise to carry out their scheme.
The mission proves fruitful, and David persuades Dawson to collaborate with them. He proposes a deal: in exchange for providing Dawson with the crucial evidence, he seeks immunity for both himself and Rebecca. Dawson, seeing the merit in their proposal, agrees. David subsequently releases Oliver, having strategically powered on Oliver's phone during his encounter with Dawson, aiming to mislead Juno into believing Oliver had met with Dawson.
Juno's team locates and apprehends Oliver. Meanwhile, the undisclosed traitor within Dawson's ranks informs Juno that Dawson had momentarily lost contact with his security. Juno's team further notes that Oliver's phone was active near the location where Dawson held his covert meeting. Juno greets Oliver's return with a mixture of camaraderie and suspicion, pondering why David would have set him free. Little does she know, this is precisely the outcome David had hoped for.
