A priest unwittingly happens upon three eccentric nuns living at a monastery on a remote island, shattering their peaceful existence.

Frankie begins a search for her missing brother as the nuns issue Ignatius an ultimatum: wed himself to their order or face certain death.

A lifetime of lies causes a divide between Carla and her sisters; Iphigenia is forced to deal with her past in order to face her future.

Ignatius' memorial takes place on the mainland; Father Bob arrives to take down the Sisters of St Agnes; Iphigenia has to decide whether to make a deal with the devil to save the monastery.