Cassandra is a 31-year-old public relations employee who values routine, struggles with social cues, and experiences synesthesia, seeing emotions as colors. Feeling isolated and out of sync with those around her, she discovers an unexplained ability to rewind time in small increments. She uses this newfound power defensively, attempting to undo minor social missteps and preserve her relationship and living situation.

Will is a 34-year-old wildlife documentary filmmaker who is enthusiastic, adventurous, and distinctly different from Cassandra in his temperament. He enjoys spontaneous activities and possesses a relaxed approach to life. He attempts to be accommodating of Cassandra's rigid boundaries, though their contrasting communication styles often lead to misunderstandings.

Artemis is a 29-year-old woman with a restless, adventurous spirit who frequently travels the globe and experiences life in shades of gray rather than absolutes. She persistently attempts to reach out to Cassandra after a decade-long period of silence following a traumatic shared past. She is highly emotional, extroverted, and actively seeking reconciliation.

Sophie is a 22-year-old colleague of Cassandra's at the PR agency who holds first-class honors degrees in mathematics and physics. Initially perceived by Cassandra as annoying and difficult to read, she proves to be highly competent and surprisingly supportive. She uses others' tendency to underestimate her as an advantage in the workplace.

Salini is Cassandra's flatmate who cycles through different hobbies and passions, expressing uncertainty about her life's direction. Though initially angry and distant due to the friction in their living situation, she possesses a strong capacity for empathy and kindness. She struggles to balance her relationship with her boyfriend and the dynamics of the flatshare.

Derek is Salini's boyfriend and a frequent presence in the flatshare. He is manipulative, arrogant, and persistently crosses boundaries, particularly when interacting with Cassandra. He weaponizes his perceived normalcy to gaslight others, consistently dismissing his inappropriate behavior as mere friendliness.

Barry is Cassandra's boss at the public relations firm who struggles to manage her direct communication style. He prioritizes client satisfaction over employee well-being and frequently expresses exasperation with his staff's refusal to conform to typical workplace social niceties.

Jack is the demanding and insensitive owner of the men's skincare brand, SharkSkin. He expects PR campaigns to adhere strictly to his aggressive, outdated marketing visions and frequently makes condescending or inappropriate remarks toward the women working on his account.

Gareth is the co-owner of the men's skincare brand SharkSkin. He operates alongside Jack as a difficult client for the public relations agency. His demands contribute to the challenging professional environment the PR team must manage.

Cameron is a colleague at the PR firm whom Cassandra mistakenly calls Ronald for much of her employment. He shares several of Cassandra's aversions to loud, overwhelming environments and relies on noise-canceling headphones to cope with corporate events.

Dandelion is a dog belonging to Will's former partner. Will temporarily cares for the dog while the owner is out of town, leading to a surprising discovery for Cassandra when she visits his home.