Catherine is the third of five novels in The O'Leary Family Series, following Caprock, Texas (book one in the series), which introduced Burn and Ciara O'Leary, and Anne Marie (book two in the series). Anne Marie was conceived when Ciara was raped by a drug cartel member before her marriage to Burn, who fought off a number of cartel members who were trying to prevent Ciara from testifying against her rapist. Burn and Ciara decided to keep Anne Marie after her birth.

Catherine, and her twin brother, Andrew, are the couple's first legitimate children. This book follows the life and loves of Catherine, and, eventually, the lives and loves of her children, James and Katie.