Julia Goulding and Jack P. Shepherd as Shona and David Platt. Cassie Plummer reaches breaking point over Ross WilkesClaire Sweeney as Cassie Plummer. While Tyrone, Tracy Barlow (Kate Ford) and Ross raise a glass to the future, Cassie can barely hide her fury. Later in the week, when Fiz Dobbs (Jennie McAlpine) insists on hosting a birthday tea for Ross, Cassie reaches breaking point. Sarah Platt is struggling on the insideTina O'Brien and Jack P. Shepherd as Sarah and David Platt.