Kill the Queen is the second episode of the fourth season of Vikings. It is the thirty-first episode of the series overall. It first aired on February 25, 2016. It was written by creator Michael Hirst and directed by Ciarán Donnelly.
Ragnar and Floki are still at odds. Rollo makes great attempts to win over his new bride, Princess Gisla. Bjorn's survival skills are put to the test. King Ecbert sets the task for his son Aethelwulf to rescue Queen Kwenthrith.
Bjorn has ventured off alone and must contend with the harsh conditions of the Scandinavian winter. Engaged in a love/hate relationship with her self-centered husband, Helga frees Floki from his bonds. Ragnar confronts Helga, who admits what she has done, and he tells her he understands. Bjorn's younger half-brother Ubbe accompanies the manhunt and discovers Floki hiding in the stream. Ragnar chains Floki in a cave. When Aslaug defends Floki's actions, Ragnar knocks her down. Ragnar finds Helga digging a grave in the frozen ground for her deceased daughter Angrboda, of whose death she has not yet told Floki. In Wessex, King Ecbert proposes a military buildup and a plan to rescue Queen Kwenthrith of Mercia and her child, who are being held by rebel nobles. The King's son, Aethelwulf engages in brutal hand-to-hand battle and eventually rescues Kwenthrith. Little does Aethelwulf know, his wife Princess Judith is now sleeping with his father. Duke Rollo makes an attempt to fit in by cutting his hair and dressing appropriately, but continues to be mocked by his new wife Gisla. Rollo suggests building forts, with a chain that can stretch the width of the river, to prevent the Vikings from sailing up river.
- Travis Fimmel as King Ragnar
- Clive Standen as Duke Rollo
- Gustaf Skarsgård as Floki
- Alexander Ludwig as Bjorn
- Alyssa Sutherland as Queen Aslaug
- Linus Roache as King Ecbert
- Amy Bailey as Queen Kwenthrith
- George Blagden as Athelstan
- Moe Dunford as Prince Aethelwulf
- Maude Hirst as Helga
- Owen Roe as Count Odo
- Jennie Jacques as Princess Judith
- Seán T. Ó Meallaigh as Prudentius
- Morgane Polanski as Princess Gisla
Additional Cast (in order of appearance)
- Mark Fitzgerald as Warrior
- David Shannon as Noble 1
- Chris McHallem as Noble 2
- Malcolm Douglas as Noble 3
- Stephen Rockett as Hvitserk
- Luke Shanahan as Ubbe
- Rosalie Connerty as Angrboda
- Des Carney as Waerferth
- Conor O'Hanlon as Alfred
- Huw Parmenter as Roland
- Karen Hassan as Therese
- Paul Ward as Hairdresser
- Philip O'Sullivan as Bishop Edmund
- James Quinn Markey as Ivar
- Aron Hegarty as Mercian Commander
- Finn and Luca Ryan as Magnus
- Michelle O'Flaherty as Shield-maiden
- Caroline Simonnet as Mercian Guard
- Gemma Weston as Mercian Guard
- Katheryn Winnick, Ben Robson, Lothaire Bluteau, John Kavanagh, Peter Franzén, Jasper Pääkkönen, and Kevin Durand are not credited and do not appear in this episode.
- Recent archeological evidence indicates women may have been more involved in illuminating manuscripts than previously thought. A nun's remains showed traces of chemicals used in painting manuscripts.
- The way Prudentius tastes the wine is absolutely correct, but at this time, the wines were not as they are now. Wines were quite different and generally heavily laced with spices.
- Floki's capture and imprisonment is based on the capture and imprisonment of the Norse God, Loki. After having Odin's favorite son, Baldr, killed, Loki runs away and Thor is sent out to capture him. Loki tries to escape by transforming into a fish and hiding in a pool, but Thor catches him regardless. As punishment, Loki is tied up in a cave, his bindings made from the entrails of his son, Narfi, and has a snake hung over him, which constantly drips poison onto Loki's head, causing him great pain. Loki's wife, Sigyn, holds a bowl over her husband's head to catch the poison, but has to leave every now and then to empty the bowl, allowing the poison to land on Loki again. It was believed that when this happened, Loki's cries of agony were the cause of earthquakes.