Iona Sheehan arrives in Ireland seeking belonging and instead finds cousins Branna and Connor O'Dwyer, a heritage steeped in witch-magic, and an ancient sorcerer named Cabhan whose evil has persisted since the thirteenth century. Together with three friends — each bringing their own strength and, eventually, their own love story — the cousins form a circle of six bound by blood, friendship, and the shared duty to end Cabhan's threat once and for all.

The trilogy rotates among three female leads — Iona's optimism, Meara's warrior spirit, and Branna's formidable strength and selflessness — each a fully realised woman whose love story is secondary to the larger family bond. Branna, as the anchor of the group, is the most memorable: fierce, deeply loving, and the emotional heart of everything.

Each of the three books centres on one couple within the circle while advancing the shared battle against Cabhan. The series moves from Iona's hopeful arrival and first love, through the deepening shadows of the second book, to the heartbreaking and triumphant finale where Branna and her forbidden love Finbar Burke must face what history and blood have kept apart. Magic, romance, and Irish myth blend in Nora Roberts' signature warm, lyrical style.