The Dead Girl Called Star. The Neon Pulse Chronicles, #2

Stefan is a dedicated young doctor working for the private emergency services company BioSynth Health Systems. During a perilous mission, he manages to rescue his grievously wounded mother, but at the cost of losing another life. Though his mother survives, Stefan struggles with lingering trauma and survivor's guilt. He finds some solace in working with his capable teammate Cass, a former hacker with her own troubled history.
But when Cass encounters an old acquaintance from her criminal days, buried secrets threaten to surface. As Stefan contends with vivid nightmares that disrupt his sleep, he resorts to questionable methods to maintain his functionality amid increasing pressure. Meanwhile, Cass dives back into the sinister world of an underground hacker group to investigate a series of unsettling events. Her efforts lead her to uncover mystifying revelations about advanced technologies with dangerous implications.
When a distress call leads Stefan, Cass, and their formidable new teammate Tera, a former soldier, into a deadly standoff, they must demonstrate quick thinking and remarkable teamwork to rescue injured police officers. During the chaos, Cass is shocked to discover her dying former mentor, Detective Kane. Compelled to keep her promise to him, she retrieves a mysterious device from Kane's old drop point, setting her on the path to unravel its secrets.
Stefan and Cass find their capabilities tested to the limits as deception and danger lurk around every corner. Their fortitude and allegiance to their profession will be pushed to the brink by new threats emerging from the shadows of the past.