Red is a shelter cat adopted by the Gioppolo family. Fatty is a nameless stray who wanders into Red's backyard and begins a tentative friendship with him. She's had a horrible encounter with a human before, so she's wary of joining the family. After seeing that Red appears to have a pretty sweet life, however, she relents and becomes a housecat. Everything is going perfectly well for the Gioppolos until the cats slip up and reveal their startling secret—first to Luca, upending his school life, then to Vic, who becomes aware of the cats' gift at the worst possible moment. Fatty's previous human interaction occurred with an elderly man named Franklin Betters. Franklin is a good man whose life has taken a dark turn since the unexpected passing of his wife years earlier. The incident with Fatty will not be the last time these two cross paths. Addressing themes of acceptance and redemption, The Catalysts is for animal lovers of all ages and for parents to read with their children.