Kentarō Momose is a 26-year-old office worker in the Planning and Sales department at the Minette advertising agency, originally from Hokkaido. He endured prolonged power harassment at a previous "black company" under his boss, Kurono. This harassment involved verbal abuse, physical assaults like kicking and shoving, destruction of his work reports, confiscating his phone to delete contacts, and deliberate exclusion from workplace communications. The sustained abuse caused significant physical and mental health deterioration, resulting in an ulcer, clinical depression, and post-traumatic stress disorder (PTSD). His PTSD manifests as severe stomach pain during stress, flashbacks triggered by phone calls or raised voices, and persistent anxiety in professional settings. An advertisement for a Tokyo planetarium created by Yūsei Shirosaki provided Momose with hope, motivating him to leave his toxic job. He joined Minette, where Shirosaki became his direct supervisor. During his job interview at Minette, Momose shared how Shirosaki's planetarium ad inspired his career change, though his nervousness prevented him from recognizing Shirosaki as an interviewer. Initially fearing his new boss would replicate his past trauma, Momose found Shirosaki's behavior quickly alleviated his concerns. Shirosaki demonstrates consistent kindness and empathy, such as purchasing medication for Momose during a stress-induced stomach ache on their first client visit, albeit mistakenly selecting menstrual cramp medicine due to his airheaded nature. Momose's personality blends innate kindness and excitability with deep-seated trauma responses. He exhibits enthusiasm during positive experiences like business trips to hot spring resorts but remains vigilant about professionalism. His trauma causes him to misinterpret neutral interactions as potential criticisms or threats, leading to overreactions and self-doubt despite recognized competence in advertising. His relationships are central to his development. Shirosaki's unintentionally comedic yet supportive actions, like offering Momose a spare apartment key to visit his newly adopted cat Hakutou—an act bystanders misinterpreted as romantic—gradually build Momose's sense of security. This key offering and later cohabitation, initiated when Kurono threatened to stalk Momose at his apartment, further strengthened their bond. Hakutou, a cat abandoned by its previous owner for scratching furniture, becomes significant. Momose, a self-professed cat lover, formed an immediate connection with Hakutou, whose full name combines syllables from both Shirosaki and Momose's surnames. Other colleagues, including Mitsuo Aoyama and Aigo Kinjō—who also escaped abusive workplaces—provide additional support. Kinjō openly identifies as bisexual. Across the series, Momose undergoes measurable healing from his trauma. While PTSD symptoms like stomach aches and panic attacks persist, their frequency and intensity diminish as he internalizes the safety of his new environment. Defining moments include defending his advertising proposals without debilitating fear, confronting Kurono's ongoing harassment with increased resilience, and eventually moving out of Shirosaki's apartment to live independently—symbolizing his recovery and reduced reliance on external support. The presence of Hakutou and positive workplace interactions facilitate his emotional stabilization, demonstrating incremental progress toward mental well-being.