Donal is a 14-year old who develops a passion for greyhound racing. He works in a kennel, which is owned by Good Joe. Good Joe promises Donal ownership of Donal's favorite greyhound, The Mighty Celt, if the animal wins three races in a row. Meanwhile, Donal's mother, Kate, must adjust her life when O, a man from her past, returns. The political climate of Ireland serves as the backdrop of this story.

Violence erupts in north Belfast when the residents of Glenbyrn, a predominantly Protestant suburb, object to schoolgirls walking through their neighbourhood from the Catholic area of Ardoyne to the Holy Cross primary school.