Helga brings her newborn girl to Floki at the docks. He is amazed but then asks Helga to take her back. He wants to name the baby Angrbooda, after Loki's first wife. Helga thinks that it's an evil name but Floki says she was a great giantess. He urges her to go home while he stays in Kattegat.
A ship arrives carrying members of Horik's family. He introduces them to Ragnar as the whole town welcomes them. In the great hall, Horik says that more than ever he now considers Ragnar an equal. He says Wessex is only the beginning and they will explore the world together, with their families joined by marriage. At the celebration, Floki reminds Horik of the proposition he had. Horik isn't sure he can trust Floki though.
Bjorn finds Porunn and asks what she will do with her freedom. She says she has plenty of choices and implies that she won't choose Bjorn.
Siggy asks Horik for his plans in Kattegat but he only says his family is there. Floki talks to Torstein about two woman before confronting Athelstan about coming back. He accuses him of being the reason Rollo will die. Horik asks Floki to prove that he's on his side and asks him to kill someone who matters. Floki looks around the room at his possible targets.
Outside, Horik watches as the Vikings of Kattegat play a game. He meets with Floki after to ask about his victim. Floki says that he knows who he will kill.
Floki travels through the wilderness and picks a plant.
Horik, Ragnar, and Lagertha decide that those who want to farm can stay on Ecbert's land while those who want to raid can go elsewhere.
Floki visits Siggy and asks about Rollo. He offers to let Siggy sleep while he watches over Rollo. Floki shows the mushrooms he picked and forces Rollo to eat them.
At dinner, Floki gives a mushroom to a child to pass onto Torstein. He warns the child not to say who sent them. Floki watches as Torstein eats the mushroom.
Bjorn stands over Torstein's body and swears revenge on his murderer. Floki agrees with Bjorn as the child who passed the mushrooms stares at the body.
Horik meets with Floki and says he can now trust him. He plans to kill Ragnar's entire family. Floki asks about Bjorn and Horik tells him to find a way to kill him. Horik says that it's all set to take place tomorrow.
Lagertha and Auslag stand at the water's edge watching a storm. Auslag says the gods are coming.
The next day, Bjorn finds Porunn and asks what she wants. She just wants respect and suggests that Bjorn fight her.
Rollo struggles to walk with a cane. Siggy tells him not to give up but he doesn't see why she cares. She thinks he can still be useful but he doesn't who could use him. Siggy places his axe in a chair before leaving. She runs into Horik, who asks for Ragnar's weaknesses. Siggy informs him that the weakness is his children. Horik asks Siggy to go to the great hall and kill his young sons. In return, he will take her as his second wife. Horik slips her a knife before walking away.
Bjorn goes with Porunn to a clearing where she starts to fight him. He asks her not to do it but she continues to fight. She runs away when she gets a chance and Bjorn follows after her. Floki watches from the shadows. Bjorn finds Porunn waiting for him at a tree. Floki sneaks up on them as they're having sex and pulls out his sword.
Horik shows Erlendur the sword of kings. He says they must overcome Ragnar today and kill all of his family. If Erlendur follows orders, one day the sword will be his.
In a forest clearing, Ragnar asks Athelstan to teach him one of his prayers. As they are praying, two boatloads of Horik's men arrive near the town.
Siggy leads Ragnar's youngest sons away from Auslag. Horik's wife Gunnhild suits up in armor as everyone prepares to attack. Horik and Erlendur lead the men into town. They attack all of the guards the come across and start several fires.
Rollo sits up and attacks the men who enter his house. Athelstan says a prayer before attacking Horik's men.
Lagertha marches to battle with her troops to Gunnhild's building. They enter by force and Lagertha kills Gunnhild. Lagertha looks at Horik's family hiding in a back room. A man tells her to leave because he has orders from Ragnar.
Bjorn fights off an attacker and asks Floki where he has been. Floki says he's been looking after him as he promised Ragnar.
Horik and Erlendur enter the great hall and confront Ragnar. They instead find Torstein and an ambush. Floki denies betraying the gods and says that he only betrayed Horik. He has always been true to the gods and Ragnar. Horik asks that Erlendur's life be spared. He walks forward as everyone gives him one attack. Floki walks right by and Siggy steps out. She hands Ragnar the knife that Horik gave her. Everyone leaves and Ragnar and Horik are left alone. Erlendur is forced to watch as Ragnar stabs Horik with the knife. Ragnar then headbutts him several times and keeps attacking.
Bjorn enters Horik's quarters and picks up the sword of the gods that Horik planned to pass down to Erlendur.
Ragnar sits on the edge of a cliff holding the sword of the gods.