The Leprechauns are under threat of the humans invading their domain. Their numbers have been dwindling over the centuries and the last of the Leprechauns in Ireland have sought sanctuary in the north of Ireland, high in the mountains of Mourne. Lenny, who is about to celebrate his 11th Birthday is disillusioned with his way of life that has changed substantially in the last 7 years, living underground in the roots of the trees during daylight and only coming out at night as the fear of the humans now discovering them has increased. Everything changes when a family of Leprechauns disappear, Lenny, his grandfather, and his friend Soil, are caught up in danger as they go looking for help in the most unlikely places. Betrayed by the Sprites, Lenny and Soil, now separated from the other Leprechauns, have to fight for their survival in a harsh environment as they encounter mythical and magical creatures along the way.