All 20 episodes from the fourth season of the historical drama following the adventures of a Viking clan. The season follows Ragnar (Travis Fimmel), a Viking chieftain who, with help from his brother Rollo (Clive Standen) and wife Lagertha (Katheryn Winnick), plots to become king. A formidable warrior, Ragnar often leads his men on raids overseas.However, even as he makes a name for himself on the battlefield, Ragnar must be aware of rivals plotting behind his back in his homeland. The episodes are: 'A Good Treason', 'Kill the Queen', 'Mercy', 'Yol', 'Promised', 'What Might Have Been', 'The Profit and the Loss', 'Portage', 'Death All Round', 'The Last Ship', 'The Outsider', 'The Vision', 'Two Journeys', 'In the Uncertain Hour Before the Morning', 'All His Angels', 'Crossings', 'The Great Army', 'Revenge', 'On the Eve' and 'The Reckoning'.