In the distant past, amidst the rugged landscapes of Skull Island, Bill Randa feverishly recorded a cryptic message to a confidant, hinting at something profoundly fundamental. Pursued by a colossal spider monster, he fled for his life, ultimately hurling a mysterious bag into the unforgiving sea. As if by fate, another enigmatic creature emerged from the shadows, engaging the arachnid in a brutal clash that granted Bill a fleeting chance to escape the chaos.
Fast forward to 2013, aboard a fishing vessel, a crew member's routine inspection of their latest haul was disrupted by the discovery of an odd, unmarked packet nestled among the catch.
Presently, Cate sat in anticipation aboard her airplane, counting down the minutes until landing. Just as she prepared to disembark, the man seated beside her abruptly insisted she remain seated. Suddenly, personnel clad in hazmat suits swarmed the cabin, initiating a thorough disinfection. The man beside her scoffed, dismissing the spectacle as a futile attempt to ward off any monstrous threats. Memories flooded back to Cate—soldiers in similar protective gear, indifferent to her cries amidst a downpour.
As she traversed the airport, a stark warning sign caught her eye, detailing evacuation routes in the event of a Godzilla attack, a sight that only deepened her unease. Before entering the country, Cate disclosed her purpose for traveling to Japan: to settle the affairs of her late father. Her relationship with her mother was strained; phone conversations were marred by Cate's brusqueness and impatience. Upon arrival at her father's apartment, the realization that one of her keys fit the lock prompted her to abruptly end the call with her mother. The apartment was a shrine to her father, adorned with countless photographs—some, however, depicted him with an unfamiliar family.
A perplexing encounter ensued when a woman, whose language Cate did not comprehend, appeared. Confusion and tension mounted as the two women attempted to communicate. Kentaro, the woman's son and fluent in English, intervened, questioning Cate's presence. Her revelation that she possessed the apartment keys and that the man in the photographs was her father as well, left him astounded.
In a flashback to 1959, Lee Shaw, Dr. Keiko Miura, and her husband—the younger iteration of Bill Randa—embarked on a perilous journey to an enigmatic destination. As they traversed the treacherous terrain, Bill's uncertainty about their path was quelled by Keiko's confirmation, guided by escalating radiation levels. Amidst their journey, it was revealed that they shared a child named Monarch, adding another layer of mystery to their quest.
Bill and Keiko donned gas masks, their eyes alight with anticipation as they declared their readiness to finally prove that their theories were not mere figments of imagination. Lee, uninvolved in their research, stood by solely to ensure their safety. Together, they ventured into a restricted zone, only to discover that a boy was already prowling there, devoid of any protective gear. Unfazed, he claimed that the tales of radiation were nothing but fabrications meant to deter the curious.
As the group pressed on, they stumbled upon an uninhabited expanse dotted with numerous facilities and devoid of any trace of radiation. Meanwhile, back at Cate's location, she engaged in a conversation with her family, displaying pictures of her father, Hiroshi, alongside herself. Emiko, Kentaro’s mother, inquired if Cate knew the fate of Hiroshi. Cate’s face clouded with sorrow as she apologized and excused herself.
Elsewhere, Keiko, Bill, and Lee meticulously set up explosives. After detonating them, they uncovered something concealed beneath the surface. As the ground began to crumble beneath them, Keiko affirmed that they had indeed found the right spot.
Cate, in the meantime, confided in her mother that there was nothing left for them there. Suddenly, a deafening alarm pierced the air, sending people into a frenzy. Cate stumbled and fell amidst the chaos. Kentaro and Emiko swiftly appeared, ushering her to a safe zone designed to shield them from an impending Godzilla attack. It was then that Cate's harrowing past was finally revealed.
She had been in San Francisco when Godzilla struck. Trapped on a school bus, she had tried her best to help the children escape. As she and a handful of others made it out, a section of the floor gave way. The bus, teeming with children, plummeted right before her eyes. The memory left her desperate, and she attempted to flee the safe zone. However, Emiko intervened, calming her down.
Meanwhile, Keiko and her companions stumbled upon a staggering number of eggs underground. Keiko surmised that they must belong to a new variant of M.U.T.O. Despite Lee's insistence on retreating due to the danger, Keiko and Bill were determined to get closer. Without hesitation, Keiko began descending, prompting Lee to follow suit and offer his assistance.
A new message echoed through the area, assuring people of their safety and permitting them to exit the safe zone. Kentaro guided Cate to the former workplace of their father. Hidden behind a peculiar map, they discovered a safe. Cate managed to unlock it, revealing the same packet that had been shown at the beginning of the episode. It bore the same symbol that Cate had seen emblazoned on the soldiers' uniforms during the Godzilla attack in San Francisco.
Kentaro entrusted the packet to May, a friend capable of accessing the encrypted files within. Initially hesitant, she agreed to help after Kentaro explained the gravity of the situation. Despite the encryption, May effortlessly gained access. However, her actions did not go unnoticed. Someone alerted her superior, revealing that the files bore the Monarch symbol. May could only provide the location from where the files had been accessed, prompting her superior to make another call.
May stumbles upon a trove of files that leave her utterly bewildered. Yet, for Cate and Kentaro, one particular file stands out—it bears a striking resemblance to a map displayed at Cate's father's workplace. Seizing the moment, Cate confides in Kentaro, unravelling the reasons behind her strained relationship with her father.
A few days had elapsed since Godzilla's catastrophic rampage when her father finally tracked her down. Relief washed over her at the sight of him, but his words were a mere whisper of apology, accompanied by cryptic instructions, before he vanished from her life once more. Not long after, a harrowing call reached her and her mother, revealing that the plane her father had been aboard had vanished without a trace.
Resuming their exploration of the files, they stumble upon another familiar sight. Among them lies an image of an enormous footprint, with a figure standing within it—none other than Keiko, their very grandmother.
Flashback to 1959, Keiko is seen meticulously gathering a sample from a cluster of eggs. Suddenly, the edifice they inhabit begins to crumble, jolting some insectoid beings from their slumber. Lee and Keiko sprint for safety, but their path is obstructed by a horde of monsters. Keiko's attempts to scale the debris are thwarted as the creatures tug at her relentlessly. Despite Lee's valiant efforts to fend them off with gunfire, their assault proves futile. In a tragic turn of events, Keiko loses her footing and plunges, seemingly meeting her doom.
