The hum of the transport vehicle was a low thrum against Rebecca Chambers’s senses, a stark contrast to the cacophony of screams and the sickening thud of decaying flesh that had filled her ears just hours before. She leaned back against the worn leather of the seat, the cool surface a welcome sensation against her flushed skin. Outside the tinted window, the sprawling cityscape of Chicago blurred into streaks of light, a stark reminder of the world she fought to protect.

It had been a few years. A few years since the suffocating tendrils of mind control had been severed, restoring her to herself. The incident had left its mark, a subtle tremor beneath the surface of her composure, and while she remained dedicated to the fight against bioterrorism, the battlefield had shifted. No longer a frontline agent, Rebecca had turned her formidable intellect towards the insidious, microscopic threats that plagued humanity.

The devastating global bioterror attacks of 2015, a dark chapter etched into the annals of history, had spurred her research. Her focus narrowed with an almost singular intensity: a cure. A cure for the virulent new strain of virus unleashed by the notorious bioterrorist, Glenn Arias. Her sanctuary for this vital work was the Alexander Institute of Biotechnology, a beacon of scientific endeavor nestled within the heart of Chicago.

Then came the storm. The sudden, brutal incursion led by the mercenary María Gómez, a whirlwind of violence that swept through the institute’s halls. Panic erupted, followed by the chilling realization of infection, the grim transformation of colleagues into grotesque parodies of their former selves. Rebecca, however, had been spared. Her proactive vigilance, a testament to her foresight and unwavering dedication, had led her to develop a prototype vaccine. She had administered it to herself, a gamble that had paid off when the very weapon meant to destroy them had passed over her, leaving her untouched.

It was in the aftermath, surrounded by the encroaching horror, that Chris Redfield and his BSAA soldiers arrived, a force of grim determination cutting through the infected horde. Their timely intervention had been a lifeline, pulling her from the jaws of despair. As she surveyed the grim scene, a chilling familiarity settled upon her. The eerie similarities between this new viral strain and the ancient Las Plagas parasite, weaponized by the cult Los Iluminados a decade prior, were undeniable. This observation was the key, a thread that linked past horrors to present threats.

It was this insight that had prompted the current journey. Accompanying Redfield, Rebecca was on her way to meet with Leon S. Kennedy, a man whose experience with the Plagas parasite was unparalleled. His unique expertise was crucial if they were to stand any chance of confronting Arias.

During a brief lull in the operational briefing, BSAA agents Nadia and Damien had casually inquired about her career shift. Why, they’d asked, had she traded the structured rigor of law enforcement for the volatile world of scientific research? Rebecca had offered a clear, succinct answer, her voice steady despite the undercurrent of weariness. While Chris, she’d explained, fought bioterrorism with his muscle, she fought it with her knowledge. It was a simple dichotomy, yet it encompassed the entirety of her purpose.

Now, in the relative quiet of the transport, Rebecca leaned back, her gaze fixed on the passing cityscape. The reflection in the window offered a stark portrait: tired eyes, the subtle etchings of past trauma and the ever-present weight of her current responsibilities evident in the slump of her shoulders. The fight was far from over.