Set on a remote Scottish island, the film follows siblings Isla and Sandy (Rankin and O’Rourke) who have lived a totally normal life for decades, hunting seabirds, chatting to mythic creatures and defending their isle from dreaded Incomers. Their world is upended with the arrival of Daniel (Gleeson), an awkward council worker, come to uproot them to the mainland. While Daniel brings strange new discoveries, Isla and Sandy teach the outsider the ‘ways of the gull’. Together, the trio are forced to confront the truth about their respective isolation.