Vikings Season 2 Spoilers Bjorn's knees go weak in "Vikings" April 3 during "Unforgiven.' Photo: Vikings

Note to self: Don’t mess with a Viking. That’s the harsh lesson we learned while watching the most brutal episode of “Vikings” yet. We’re not kidding. If you thought the battle between Rollo and Ragnar was gruesome, just wait until you see episode 6, “Unforgiven.”

The hit History Channel series began with Siggy paying a visit to Kattegat’s seer. According to Rollo’s lover, she’s still pretty upset over the fact that Ragnar killed her former husband, stripping her of her power. Siggy said she felt as if she’s been carrying around a stone of anger and bitterness.

“Everything I was has been stripped away from me,” she confessed. “I want to know if the gods will ever smile on me again.”

The seer assured her that the gods would always smile on brave women. Looks like we can expect big things from Siggy from here on out.

Episode 6 then cuts to a scene between King Horik and Ragnar. After returning home from Wessex, Horik reveals what happened in England when Ragnar left to protect his family.

“We were betrayed and taken by surprise,” he said. “It was a great slaughter.” The king and his son barely made it out alive.

Ragnar questioned what happened to Athelstan, but no one seems to know. Horik believes he was killed during the ambush, and Floki couldn’t be more thrilled with his prediction.

“We should rejoice of his death,” he quipped. Floki has never trusted the pagan wannabe.

During King Horik’s homecoming feast, he explains to Ragnar that he wants revenge on King Ecbert. Rollo and Ragnar both agree.

“We should return to Wessex. But first Jarl Borg must pay the price for what he did to our family,” Ragnar said.

At that moment, a pretty slave girl spills water on Bjorn. She’s quite embarrassed, but he thinks nothing of it.

“We shall sail west. That was your dream, Ragnar, and I have come to share it. But we have neither the men nor the ships. I think we should go back to Jarl Borg. He’s licking his wounds. He’s not strong. Yet, we need him. We cannot go west without his ships. We should ask him to join our alliance,” Horik explained.

Aslaug urges her husband not to listen to the king's advice. But Horik and Ragnar agree that Rollo should be the one to talk to Borg because he “knows him best.”

After the dinner party, Siggy joins Horik and his son for a chat. Siggi is confused as to why the boy is there, but Horik says that he wants his son to witness the “game” they play.

“Why do you invite me to your bed? Tell me things about Ragnar?” Horik asks.

Siggy replied that everything she does, she does for Rollo.

“If Rollo rises, I rise also.”

Is she using him? Seems like it.

After Siggy’s admission, Horik reveals that he wants the brunette beauty to turn his son into a man. She toys with the idea but ultimately gives in and sleeps with the boy.

Siggy isn’t the only facing issues with men. Lagertha also received a not-so-warm welcome back home.

“My wife has returned to me. That’s good,” the Earl said. “She went without my permission. I love her [for coming back].”

Sigvard then raised a glass to Lagertha before admitting, “Unfortunately, you left my step-son behind.”

Lagertha explained that her son wanted to stay with his father.

“He’s old enough to decide. Is it not enough I came back?” the shield maiden asked.

“It’s not enough. It’s an insult to me,” he replied. That’s when Sigvard began mocking Ragnar. Lagertha didn’t look too pleased. The Earl wondered why his wife was defending her former lover.

“You’re still in love with him. Aren’t you?” Earl Sigvard stumbled off in his drunken state, telling his wife she is to sleep alone tonight.

That night Lagertha is brutally attacked by a handful of masked men. She is beaten unconscious after attempting to defend herself.

Unaware of his mother’s suffering, Bjorn is enjoying his time with his father — especially because the slave girl who previously spilt water on him has caught his eye.

He walks up to her during her chores, asking her personal questions from where she sleeps to if she has a boyfriend.

“Of course,” she said. “I must finish my work.”

Ouch, Bjorn! But the young warrior refused to give up on the beautiful slave girl. Eventually, he invites her back to his home. He requests she sleeps in comfort instead of in the barn with animals.

“This is your place. I cannot sleep here,” she replies.

“I don’t want to order you. I want you to choose to stay here,” Bjorn says.

That’s when the young woman starts stripping off her clothes.

“Is this what you want, master?” she asked.

Ragnar had spotted his son initially flirting with the slave girl. As he looked upon the awkward incident, Aslaug begins firing questions regarding Horik.

“Why do you let Horik decide everything? Do you really forgive Jarl Borg? Do you know how much I, how much your sons have suffered because of him? But you do nothing about it,” she complained.

Something is up Ragnar’s sleeve, right?

Rollo finally makes it to Gotland, Scandinavia, where he meets with Jarl Borg to convince him to raid alongside Ragnar and Horik.

During their discussion, Borg puts the skull of his first wife on the table to “give him advice.” OK, so Borg is officially crazy.

Rollo insists Ragnar isn’t looking for revenge, and with that Jarl Borg decides to make another trip to Kattegat.

While all this is going on, Athelstan is still alive and kicking. He’s become the unofficial right hand of King Ecbert due to his kindred spirit. Ecbert reveals that he wants the on-again, off-again pagan-Christian to help preserve the work of the pagan Romans.

“Never speak of our conversation to any other man here. They would fear it. The fact is we have lost more knowledge than we ever had. Pagan gods allowed them [Romans] to rule the world. And what is the lesson we can learn from that?” Ecbert asked. He then threatened Athelstan that if he was to reveal to anyone what he was doing, that he would let the Christians crucify him.

Ragnar and Jarl Borg finally reunite after their battle in Kattegat.

“You are a greater man than I am,” Borg says. “I swear from henceforth you have no reason to doubt my commitment of loyalty.”

Ragnar admitted that he initially he wasn’t thrilled with the idea of teaming up with the man who threatened his family. But, then he thought of the things he could achieve with Borg's help. Hmm, is anyone really buying this?

The most brutal scene of episode 6 follows Ragnar’s talk with Borg. After receiving a horrific beating, Lagertha is forced to appear at dinner with a swollen face.

“What’s wrong, my love?” Sigvard asks. “You don’t talk, smile.” He aggressively grabs her face and kisses her wounds. That’s when the drama starts.

“My wife has got the most beautiful breasts. I keep telling her, but she doesn’t believe me,” he announces to the room filled with dinning guests. “Let me show you.”

Sigvard starts ripping off Lagertha’s shirt, but she quickly springs into action, grabbing a knife and stabbing her husband in the eye.

He moans in agony as everyone watches in shock. Someone picks up an axe and swings it. We think he's going to attack Lagertha, but the man chops off the Earl’s head, silencing his groans.

After that, we hear Aslaug tell her boys a story. During the tale, several events happen. Rollo sets a barn filled with Borg’s men on fire while Ragnar’s warriors go and seek out the man who betrayed Ragnar.

Borg wakes up—thanks to the whispering skull—and is armed when Rollo walks into his bedroom. Prior to Ragnar’s men entering, Borg hears the seer reiterating his prediction of the eagle.

“I told you. I always look for revenge,” Rollo said to Borg. Ragnar’s brother watches in Borg’s bed as he’s beaten.

King Horik wakes up due to all the ruckus and asks Ragnar what is going on.

“I am sorry that the army of Kattegat has awoken you,” Ragnar replies.

That’s when they drag a bloody Borg in.

“Is he dead?” Horik asks.

“He’s not dead.. yet,” Floki replies.

Horik asks why Ragnar has done this.

“Do you really think I could ever forgive this man who threatened to kill my family?” Ragnar asks before announcing he’s going to execute Borg.