An epic fantasy adventure based on the timeless Arthurian legend, The Green Knight tells the story of Sir Gawain, King Arthur's reckless and headstrong nephew, who embarks on a daring quest to confront the eponymous Green Knight, a gigantic emerald-skinned stranger and tester of men.
In 1985, while working as a coal merchant to support his family, Bill Furlong discovers disturbing secrets kept by the local convent and uncovers truths of his own; forcing him to confront his past and the complicit silence of a small Irish town controlled by the Catholic Church.
When the ongoing rivalry between farmers Michael and Jack suddenly escalates, it triggers a chain of events that take increasingly violent and devastating turns, leaving both families permanently altered.