Guest Stars Dominic MacHale as Sergeant Healy Demi Isaac Oviawe as Linda Walsh Jennifer Barry as Siobhan Walsh P.J. Gallagher as Principal Barry Walsh Orla Fitzgerald as Orla Walsh Shane Casey as Billy Murphy Nola Richardson as Star Penny Richardson as Star Ciaran Bermingham as Superintendent Flynn John Murphy as Guard Rachel O'Connell as Nancy Madigan Daniel Power as Gavin Madigan Thomas McCarthy as JP Claudia Rose Long as Niamh Adrian Scanlan as Derek Doherty Cian Hurley as Bobby Gilligan Eoghan Moloney as Compère