After the death of his brother in a freak hurling accident, 13-year-old Lorcan Cullen has shut out the world - his hurley stick buried, his heart guarded, his only solace a pair of headphones and a battered drum kit. But everything changes on a school trip to Newgrange, when Lorcan encounters the mythical Staff of Dagda: a relic said to bring life with one end and death with the other.

Convinced he can undo the past, Lorcan - alongside his benevolent classmate Caitlin and loyal dog Cú - journeys through a portal to the Celtic Otherworld on Halloween night to activate the staff. There, the trio face treacherous landscapes, zombie warriors, and a shape-shifting foe: Morrigan, Queen of the Dead. When she seizes the Staff of Dagda to raise her army of the dead, Lorcan’s personal quest becomes a seemingly impossible race to save the world.

But as the secrets of Lorcan’s ancestry are unravelled - including a bloodline tied to Ireland’s greatest mythic warrior, Cú Chulainn - Lorcan embraces his destiny. He also discovers the true cost of grief and the power of letting go.