Karen Fisher is the former Headmistress of Waterloo Road, replacement of Rachel Mason and predecessor to Michael Byrne. She is the mother of Jess and Harry Fisher. She is also the mother of Bex who later appears. On Karen's first day in the new job, new girl Ruth Kirby walks out of the school and goes missing for over six hours until she is found in darkness by Francesca Montoya and Tom Clarkson. Whilst the search party is being carried out, Karen is getting flashbacks of what it felt like when she lost her daughter Bex.