Guest Stars Elijah O'Sullivan as Jacob Dwyer Conor Mullen as Frank Ahern Carrie Crowley as Mairead Noonan Justine Mitchell as Elaine Lynch Éanna Hardwicke as Joe Ryan James O'Donoghue as Calum Dwyer Hazel Doupe as Ingrid Jensen Ayoola Smart as Cathy Cregan Hilary Rose as Alanna Hutchins Lochlainn O'Mearáin as Rory Dwyer Stuart Graham as Denis Ahern Clodagh O'Rourke as Baby Nell Michael Patric as Sgt. Paudie Manning Thomas Levin as Carl Jensen Kevin McGahern as Michael Foley Tristan Heanue as Ronnie Dillon Levi O'Sullivan as Alfie Dillon Tim Casey as Desk Sgt. Ciaran Noah James Flynn as Young Calum Huey O'Meara as Young Jacob Shane G. Casey as Priest