Guest Stars Conor Mullen as Frank Ahern Carrie Crowley as Mairead Noonan Justine Mitchell as Elaine Lynch Elijah O'Sullivan as Jacob Dwyer James O'Donoghue as Calum Dwyer Hazel Doupe as Ingrid Jensen Hugh O'Conor as Dr. Kevin Stuart Graham as Denis Ahern Lochlainn O'Mearáin as Rory Dwyer Michael Patric as Sgt. Paudie Manning Thomas Levin as Carl Jensen Tristan Heanue as Ronnie Dillon Carolyn Bracken as Sandra Dillon Levi O'Sullivan as Alfie Dillon Tim Casey as Desk Sgt. Ciaran Holly Sturton as Elsa Malcolm Adams as Pascal Joe Gallagher as John Kelleher Fiona Browne as Claire Riordan Jerry Fitzgerald as Barney