No. of episode	Title	Original air date
1	"Mercenary"	February 19, 2015
Ragnar tells Björn that he never wanted to be king, but only to explore and farm. Ragnar wants to return to Wessex to claim the land promised by King Ecbert. Floki feels that his new family with Helga is too happy, while Rollo wishes to be away from Siggy. Þórunn desires to be a shield-maiden like Lagertha, much to Björn's displeasure; he believes her to be carrying his child. When Lagertha announces she intends to raid with Ragnar, Kalf, her right-hand man, offers to remain and take care of Hedeby. When they arrive in Wessex, King Ecbert informs Ragnar that to receive their land, the Vikings must fight for Princess Kwenthrith to appease King Ecbert's nobles. Lagertha is unsure about joining, so King Ecbert offers her the job of leading the Viking settlers in Wessex. The settlers go to the land to farm, while the warriors defeat Kwenthrith's uncle's army.
No. of episode	Title	Original air date
2	"The Wanderer"	February 26, 2015
A celebration is held in honour of the victory. Kwenthrith asks for the head of her uncle, and Ragnar questions her hatred; she admits to having been sexually abused as a child by him and her oldest brother. Concerned about Þórunn's safety, Björn lectures and then proposes to marry her. In Kattegat, Helga, Siggy, and Aslaug share strange dreams about a hooded stranger walking in the mist, one hand bloody and the other holding steaming snow. In Hedeby, Kalf usurps the earldom with the help of Einar. Prince Aethelwulf searches for the young brother of the princess and his army. He captures a soldier who tells him that they expect reinforcements. Torstein's left arm becomes gangrenous and he asks Floki to amputate it. King Egbert, woos Lagertha and offers her a necklace. Princess Judith tells Athelstan during confession that she dreamt of sleeping with him, and they share a kiss. In Kattegat, Helga meets the stranger from her dreams who is wounded in the right hand.
No. of episode	Title	Original air date
3	"Warrior's Fate"	March 5, 2015
Helga, Siggy, and Aslaug help Harbard with his hand. He explains that he is a wanderer, offering to share stories about his travels, and the gods, in return for lodging. In England, Floki resents Ragnar's fighting for the Christians. The Vikings begin climbing the mountain to fight Kwenthrith's brother and his army. She asks Ragnar to spare her brother. Torstein volunteers to go first, and dies valiantly. While Ragnar and his men fight their way up the hill, Aethelwulf's archers surround Kwenthrith's brother, killing many and forcing him to surrender. Þórunn is severely injured. Ragnar finds out that Þórunn is pregnant, and chastises his son for having allowed her to fight. In England, King Ecbert shows Lagertha his Roman bath house, and invites his guests to join him in the bath. Later, Athelstan finds Ecbert and Lagertha having sex. In Kattegat, a fisherman catches two drowned young boys in his nets. Siggy visits the Seer to discuss Harbard and her dreams.
No. of episode	Title	Original air date
4	"Scarred"	March 12, 2015
Aethelwulf attempts to befriend Rollo and Floki; Floki is unhappy about fighting for Christians. Athelstan sleeps with Judith and they both express their love for each other. Kwenthrith helps Ragnar with his wounds. King Ecbert and Lagertha have a sexual relationship but she tells him that "He only cares for himself". In Kattegat, Aslaug sleeps with Harbard. Harbard seems to be able to ease Ivar's pain simply by touching and talking to him. Kalf and Einar plan for Lagertha's return. Kalf says he has invited an important person to their village to help, who is King Horik's son Erlendur, now married to Jarl Borg's widow Torvi. Aslaug's sons run out of their home and Siggy finds them walking across a frozen pond, where they fall through the thin ice. Siggy dives in, and Harbard pulls them out as Siggy drowns. In England, Princess Kwenthrith poisons her brother Burgred. She then proposes a toast to herself as the sole ruler of Mercia to which all in the room acknowledge and then pour out their wine onto the floor. Before Harbard leaves Kattegat, he tells Aslaug that Ivar's pain will now be less.
No. of episode	Title	Original air date
5	"The Usurper"	March 19, 2015
The Vikings return to Kattegat, and the women learn of Torstein's death as the men learn of Siggy's. Ragnar is suspicious about why Aslaug was not watching the children. Floki becomes more outspoken about his hatred for Christians, and Athelstan. Helga tells Floki about Harbard, and he claims that Harbard is a god. Aethelwulf learns that Judith is with Athelstan's child, and he is sent to the settlement. A messenger arrives to tell Lagertha that her earldom has been usurped by Kalf; she asks Ragnar to help win it back. Ragnar tells the men that they will raid Paris in the spring. Ragnar returns with Lagertha to speak with Kalf, although he decides not to help fight for Lagertha, and instead asks him to join the raid on Paris. Aethelwulf leads his soldiers to the settlement, and kills all the settlers. Floki tells Ragnar that Aslaug slept with Harbard, and that Harbard is another name for Odin. King Ecbert finds out about the settlers' fate; he chides his nobles, then in private reveals that it was his plan all along.
No. of episode	Title	Original air date
6	"Born Again"	March 26, 2015
Þórunn gives birth to a girl that Bjorn names Siggy. A farmer returns from Wessex and tells Ragnar about Aethelwulf's massacre. Athelstan has a sign from God and tells Ragnar that he has been born again as a christian. In Wessex, Judith gives birth to a son, but is then sentenced to having her ears and nose cut off for adultery. After one ear is removed, she reveals that Athelstan is the father. King Ecbert says the child is sent from God and will be christened Alfred. Earl Kalf leads a fleet to Kattegat to join the raid on Paris, along with Erlendur and Torvi. Rollo reveals that Athelstan no longer wears his arm band. Floki receives a sign that "blood must be spilled", and kills Athelstan while he is praying. Ragnar, heartbroken by Athelstan's death, carries his body up the side of the mountain for burial, and asks Athelstan for forgiveness.
No. of episode	Title	Original air date
7	"Paris"	April 2, 2015
Ragnar's Viking fleet, also reinforced by the earl Siegfried, arrives in Francia, and prepares for battle. Emperor Charles is asked by count Odo to evacuate Paris, but after privately consulting his daughter Gisla, he refuses. Ragnar shocks them when he decides to leave Floki in charge of the attack. Both Vikings and Franks prepare for the siege as the Christians pray for protection from the pagans. In England, Queen Kwenthrith has killed the Wessex nobles and has broken her ties with King Ecbert. The king sends his son, Aethelwulf, to Mercia to force her back into submission. She informs Aethelwulf that her son, Magnus, was fathered by Ragnar. She eventually submits once Aethelwulf tells her about the massacre of the Viking settlement.
No. of episode	Title	Original air date
8	"To the Gates!"	April 9, 2015
The Vikings attack Paris. Lagertha, Kalf and Erlendur lead an attack on the city gate; meanwhile, Floki, Ragnar, Bjorn and Rollo try to breach the walls from boats on the river. Princess Gisla manages to restore faith in the Frank troops by revealing the Oriflamme, the holy banner of their patron, Saint Denis. Eventually the defense holds, repelling the Vikings with the use of oil, fire, and crossbows. While the Franks celebrate their victory, at the Viking camp the warriors have to deal with their wounded, including a badly wounded Bjorn, and Ragnar who has been thrown down from the walls. Floki is consumed by his guilt, having trusted in the good omens of their gods. Helga, disgusted by his selfishness, leaves him.
No. of episode	Title	Original air date
9	"Breaking Point"	April 16, 2015
With the Vikings still recovering, Ragnar orders another attack. Led by Rollo, Lagertha, and Kalf, they manage to pass the bridge, but they are once again pushed back. Siegfried is captured and executed on Gisla's insistence. Although the Franks have managed to defend the city, a plague has spread in Paris and citizens are dying. Count Odo begs the Emperor to come to terms with their enemy. Ragnar's wounds won't heal, leaving him weak. Trying to restore his leadership, he secretly meets the Franks; although offered gold and silver, Ragnar doesn't accept. Knowing his end is drawing near, he asks to be baptized, and to be buried inside the city. Meanwhile Aslaug rules in Kattegat, and deals with the Christian missionary Ansgar. Ansgar tries to carry a hot piece of metal to prove the might of the Christian god. When he fails, Aslaug has him killed. In England King Ecbert and Judith start up an affair.
No. of episode	Title	Original air date
10	"The Dead"	April 23, 2015
The Franks pay gold and silver to the Vikings, but they show no sign of leaving. Many people are still shocked at Ragnar's christening, and when the badly wounded leader dies, Bjorn is in charge. The warriors place Ragnar into a wooden coffin and escort it to the gates of Paris, where they meet the Bishop. The coffin is brought inside the Cathedral to be blessed, but Ragnar suddenly jumps out of the coffin alive. He takes Princess Gisla as a hostage and forces the guards to open the gates, allowing the Vikings to enter the city. Most of the Vikings then set sail for home, but a small party, led by Rollo, remain camped outside the city to maintain a presence for next years raid. Emperor Charles is determined to gain his favour, offering Rollo land and titles, and his daughter in marriage in exchange for his pledge to defend Paris against future Viking attacks. While sailing home Ragnar tells Floki that he knows he is Athelstan's killer.