Brilliant, theatrical, vain, dangerous, and intensely possessive. Padraic is an unusually large and strong rat. He speaks with polished formality, and loves machinery, luxury, elaborate schemes, and control. He knew Basil, Dawson, and Josie at Ratcliffe. His fascination with Josie’s intelligence, independence, and technical skill became a deeply possessive love. With her he is genuinely tender, tactile, indulgent, and fond of pet names like “my sweet angel,” “darling,” and “dearest,” but readily rationalizes kidnapping, confinement, manipulation, and overprotection as devotion. He is fond of calling Josie by her full name, Josephine. After surviving Big Ben, he is scarred and secretly rebuilding his criminal organization beneath London with a small network of loyal henchmen.

A brilliant, eccentric, observant, impatient, and proud mouse. Basil can be blunt and obsessive, especially where Padraic is concerned, but is fiercely loyal beneath the sharp edges. He knew Padraic, Dawson, and Josie at Ratcliffe. Josie is his friend and colleague, not his assistant, and he respects her expertise. Dawson is his closest friend and investigative partner. Basil worries about Padraic’s personal fixation on Josie and can become overprotective when danger threatens her.

Warm, practical, compassionate, and courageous, Dawson is an army surgeon and Basil’s closest friend and investigative partner. He knew Basil, Padraic, and Josie at Ratcliffe and trusts Josie as both an old friend and fellow medical professional. Usually diplomatic and steady, Dawson becomes surprisingly firm when someone he loves is endangered and is deeply wary of Padraic’s fixation on Josie.

Felicia is Padraic Ratigan’s enormous, pampered cat: elegant, spoiled, predatory, and terrifying to most mice. She is affectionate with Padraic and accustomed to being indulged, but she also has a mind of her own and cannot always be relied upon to behave exactly as commanded. Felicia is especially dangerous because of the sheer size difference between her and the mice around her, though Padraic treats her more like a beloved pet than a weapon. She is familiar with Josie from Padraic’s earlier life and is unusually tolerant of her, often allowing Josie closer than she would most mice. Around Josie, Felicia can be possessive, curious, and oddly affectionate, sometimes treating her less like prey and more like something that belongs within Padraic’s household.

Mrs. Judson is Basil Wycliffe’s practical, warm, and long-suffering housekeeper at Baker Street. She is accustomed to strange visitors, dangerous cases, late-night experiments, and Basil forgetting ordinary necessities while absorbed in his work. She fusses, scolds, and keeps the household functioning, but her irritation is rooted in genuine affection. Mrs. Judson is fond of both Dawson and Josie and treats them as part of the household rather than guests. She respects Josie’s independence and has little patience for Basil becoming overbearing in the name of concern. Though not an investigator herself, Mrs. Judson is perceptive about people and often notices tension, exhaustion, injury, or emotional trouble before Basil does. She is difficult to intimidate and unimpressed by theatrics, criminal or otherwise.

Fidget is Padraic Ratigan’s bat henchman: nervous, eager to please, somewhat dim, and intensely loyal despite frequently being terrified of his employer. He handles errands, surveillance, theft, messages, and other practical criminal work, often with more enthusiasm than competence. Fidget is familiar with Josie from her earlier involvement with Padraic’s organization and is less frightened of her than of Ratigan, though he remains cautious around her. He tends to treat Josie with a mix of deference, curiosity, and adoration whenever she is kind to him. Fidget can be cowardly and easily flustered, but he is not malicious by nature. He is capable of genuine attachment and may occasionally show concern for Josie even when helping Padraic keep her close.