Episode 4 of *Tempest* kicks off with Mun-ju, Chang-hee, and Mi-ji scrutinizing San-ho's background, debating whether he's truly qualified to serve as Mun-ju's bodyguard. His reputation precedes him—no one under his protection has ever perished—but Chang-hee remains skeptical, given San-ho's mercenary past. Despite Chang-hee's reservations, Mun-ju decides to bring San-ho on board.
As Mun-ju watches the news, she learns that President Chae has journeyed to China. Im Du-jin informs her that the US Vice President and North Korean leader Kim Han-sang have also converged in China. He speculates that China, Russia, and a nation named Idicia might be forging a formidable alliance amidst the looming specter of world war. Furthermore, he warns that the head of the CIA is in the country and could be setting his sights on Mun-ju.
Mun-ju then breaks the news to Lim Ok-seon that she will be relocating. With Baek San-ho officially commencing his duties, Mun-ju settles into her new abode. San-ho proves to be meticulous about her safety, going so far as to insist on sleeping in the adjacent room and preparing her meals.
When Ok-seon pays a visit to the new house, she pulls Chang-hee aside and implores him to investigate her own residence for the bugs she uncovered in the previous episode. She also confesses that she doesn't fully trust Mun-ju. Unbeknownst to them, San-ho overhears their entire conversation.
During another rally where Mun-ju delivers a rousing speech, San-ho's keen eye spots a suspicious individual. He urges Chang-hee to investigate, but Chang-hee dismisses the concern, asserting that the area has already been thoroughly vetted.
On the drive back home, San-ho's instincts kick in when they find themselves ensnared in a traffic jam, with a tanker looming ominously ahead. He spots the same suspicious man from the rally lurking nearby and immediately instructs the driver to make a U-turn. However, their escape is thwarted when another truck slams into their car from behind, causing the tanker to erupt in a blazing inferno. In a split-second decision, San-ho maneuvers the car to safety, narrowly averting disaster and saving everyone on board.
He hastily yanks Mun-ju to safety, guiding her through an employee entrance of the underground train station, where they cautiously tread along the tracks. Ensuring utmost secrecy, he instructs her to switch off her phone. Curious, Mun-ju inquires how he knew an attack was imminent. San-ho reveals that he spotted a distinctive tattoo on the suspicious man, a mark commonly associated with perilous Nepali soldiers.
Meanwhile, Mi-ji, who had been in the car with them, manages to reach Chang-hee and hastily fills him in on the unfolding drama. Alarmed, Chang-hee dispatches his people to scour the area for Mun-ju, even authorizing them to neutralize San-ho if he poses any threat to her safety. Eventually, San-ho and Mun-ju arrive home, only to find San-ho clashing with Chang-hee over Mun-ju's well-being.
Later, when alone, San-ho contacts Ethan, his voice tinged with frustration. He demands more information about their mysterious client, exasperated by the fact that the client is monitoring his location and eavesdropping on his calls without offering any useful intelligence. San-ho reveals that only the client and Ethan were privy to Mun-ju's route that day and, in a fit of anger, tells the client to reclaim their money, declaring his refusal to continue working for them.
Elsewhere, Chang-hee voices his suspicions about San-ho to Mun-ju. He mentions that Valkyrie is linked to a U.S. official named Eagleton, who has connections to the company implicated in the bombing from the previous episode. He even expresses doubt about the new house, which Mi-ji had located with uncanny speed. However, Mun-ju maintains that she has her own reasons for keeping a close watch on San-ho.
That night, Mun-ju is jolted awake by a nightmare. She rouses San-ho and confides in him about it. Sensing her unease, he asks if she wants to go for a run, and she nods in agreement. As they jog, Mun-ju eventually broaches the subject of the house. San-ho admits that he arranged for it due to its robust security measures. In a gesture of trust, she returns the necklace of St. Anthony to San-ho, so he may be safeguarded while protecting her. We later discover that Mun-ju has discreetly planted a bug in the necklace.
Meanwhile, Chang-hee uncovers bugs concealed within Lim Ok-seon's residence. He presents them to Ok-seon, explaining that he found the files on Jun-sang's computer. Ok-seon urges Chang-hee to keep a close eye on Mun-ju, as she still harbors suspicions about her involvement in Jun-ik's demise.
Sometime later, Chang-hee contacts Mun-ju, excitedly informing her that he has located Jun-ik's secret phone, which had been stashed away in his car. After managing to unlock the device, he stumbles upon something so shocking that it compels him to reset his entire computer. Mi-ji, happening to notice Chang-hee driving away from the office and failing to answer her calls, decides to follow him. Moments later, Chang-hee is involved in a collision caused by a vehicle ahead of him.
He is frantically rushed to the hospital in a whirlwind of urgency. Before Chang-hee is wheeled into the Intensive Care Unit (ICU), he manages to whisper a bombshell revelation to Mun-ju: Jun-ik might have genuinely been a spy. Meanwhile, Mi-ji is in possession of the clandestine phone, only to discover that Chang-hee seems to have wiped it clean as well, erasing any trace of incriminating evidence.
Just then, a text message from an unidentified number flashes across Mun-ju's phone screen, bearing an address and a snapshot of the cross necklace that Jun-ik had once bestowed upon her as a gift. Seizing the moment, Mun-ju and San-ho hasten to the provided location and gain entry using the passcode that had been discreetly shared with them.
As they explore the house, Mun-ju's eyes are drawn to a framed photograph adorning one of the walls. In the image, Jun-ik is captured alongside a woman and a young boy, their smiles frozen in time. The episode reaches its climax as the woman and child emerge from a neighboring room, their presence adding an air of mystery and anticipation to the unfolding drama.
