Instead of the summer she was looking forward to, Grainne somehow lands herself in the middle of another adventure. This time to protect the legendary Stone of Fal. Series 3 of the NYC award winner returns!

Grainne & Flaherty are looking forward to a peaceful summer spent sailing around clew bay – but a new arrival at the castle is about to change everything.

Grainne learns that her unwanted house guest, Meabh O’Kelly, is part of the clan charged will protecting the legendary Stone of Destiny. Grainne fails to make a good first impression on Meabh and things quickly go from bad to worse.

Her plans for the perfect summer officially ended, Grainne finds herself traveling with Meabh and the O’Kelly’s to Meath. While she does, Grainne receives a warning from both Diarmuid (the O’Kelly’s advisor) and the Druid that danger is near.

Grainne indulges in some petty sabotage that backfires leaving her feeling isolated and alone, her only friend in the castle now seems to be Diarmuid. The Druid continues to warn Grainne that danger is nearer than she thinks.

Meabh agrees to show Grainne The Stone of Destiny and they see a different side to Diarmuid.

Meabh and Grainne attempt a dangerous escape from the Pirate Alday.

With Flaherty, Madra, and Donal still in the clutches of Alday, Grainne and Meabh must work together to save them.

Grainne admits to Flaherty that she was jealous of Meabh. The full gang now reunited work together to defeat Alday and the evil Druid Seamus who works with him. But will the succeed?

It's the season finale! Grainne needs to escape, save the captured crew and return the Cauldron of Dagda to where it was stolen from. In her way are two villains and a band of pirates. Can she succeed?