The fourth episode of Vikings' fifth season, The Plan, begins in the country of York, King Aethelwulf is talking to Bishop Heahmund about getting rid of their pagan invaders after their previous efforts to force them out went very poorly, to say the least. Heahmund apparently had a vision that he saw all the bodies of the Northmen lying dead in the city from starving to death. So he convinces Aethelwulf to blockade all the roads and rivers in an effort to keep their foes from getting any food or supplies. While the plan appears to work fine at first, killing the Northmen's hunting parties that try to gather food, they are not aware what is going on inside the walls of York. Ivar is not scared by the tactics that the Saxons are trying to use on his people and he already has a plan to get them out of this. He has his men make fires to create black smoke so the Saxons think they are burning their dead from starvation. King Aethelwulf sees this as a sign to attack but Heahmund advises against it saying they should give it just a little more time to be sure. Eventually, their scouts would see no site of the Northmen anymore and with that, the Saxon army would break into the town of York and find no sign of the Great Army. With just stray horses and the black ash from the fires, they had been burning it appears they have fled. But Bishop Heahmund is not convinced as he is puzzled by the abundance of rats crawling around above ground.
Back at Kattegat, Ubbe has returned and he falls right back into the arms of the former slave girl now his wife Margrethe. He sits down to talk with Lagertha and even though she praises him and his brothers for avenging Ragnar's death, he has to inform her of his real reason for coming back home. He tells her of Ivar killing Sigur and him taking control of the Great Army, and of Hvitserk deciding to stay with Ivar over coming back to Kattegat. He expresses how Bjorn is well and decided to travel over taking up the mantle as leader of their people. But the point in all of this is Ubbe now feels like Ivar and Hvitserk are his enemies and he is at war with them. Lagertha immediately sensing that Ubbe is emotional and heartbroken offers that they make a pact in defeating their enemies. He helps her in defeating King Harald and she, in turn, will help him against his brothers. He is reluctant at first since she killed his mother, but then realizes this plan best serves the overall benefit of defending their people.
Only not everyone is on Lagertha's side as Margrethe tries to convince Ubbe that the queen is losing her power and the gods no longer favor her. She tells Ubbe that he should take the throne of Kattegat for himself because Bjorn does not have interest in ruling. But Margrethe would get too ambitious in her sneaky plan as Lagertha would overhear her trying to sway Torvi to her side. In a surprise move, Lagertha does not punish her but instead tells her that if she stays loyal that she will have great respect for the former slave girl.
Over on the high seas, Bjorn and Halfdan would decide to land in the town of Sicily and visit its leader Commander Euphemius claiming that they are just traders. Euphemius takes a liking to them and requests to hire them as his personal bodyguards to which they agree. But when they find out that Euphemius isn't really the leader and more of a figurehead they ask to go visit the real man in charge who is named Ziyadat Allah and lives in a country in Africa. When they approach Euphemius about visiting Allah he refuses, until a woman named Kassia who is a holy nun that the Commander stole from the holy city of Byzantium orders him to take her because he always promised he would. And with that, they would indeed set sail for Africa to meet this famed leader.
After spending several days alone on his new island discovery Floki comes to the decision that he has been blessed to find such a land that he feels is close to the gods that it needs to be shared with others. He knows he must leave this place and bring more people back with him to inhabit it because that is why he was chosen to find it in the first place. What a generous fellow. And finally, after much contemplation with herself, Astrid decides to marry King Harald. Whether she is doing it to seek the power and position that he is promising or she has ulterior motives remains to be seen!
In the fifth Season 5 episode, The Prisoner, thinking that the Viking army has fled York for good the Saxons have entered the city to verify they have left and reclaim it back for themselves. Unbeknownst to them Ivar is far more cunning than that and has his hidden his Great Army in the sewers below the city. Using ladders to climb back up from below the Vikings surprise the Saxon soldiers from underground and quickly overrun them while decimating their numbers. Realizing all is lost, King Aethelwulf grabs his wounded son and sounds the retreat of his remaining troops. During the battle, Ivar sees the ferocity of Bishop Heahmund's warrior skills and admiring his spirit makes a point to take him alive as his prisoner. The Great Army lets out a victorious cheer as they have sent their foes running away yet again.
Later on, Ivar and Hvitserk would discuss their plans for the future and predictably their attention turns to their revenge on Lagertha and taking over Kattegat. Ivar remembers how King Harald had desired to take Kattegat for himself and thinks that he should make a good temporary ally for their cause. They decide to leave a group of warriors to watch over York while they sail to go have a meeting with King Harald. Ivar decides to take Bishop Heahmund with them to see Harald because he wants him to spread true and authentic stories about what a great leader he has become. Ivar is already an evil enough conqueror but now he wants the world to know it.
At Kattegat, Floki has returned and he is telling everyone that he has found a land that is touched by the gods and everyone should come to inhabit it. He tells Lagertha about his discovery and asks to take some of the residents of Kattegat back with him to begin farming and colonizing the new country. While she has much history with Floki, she can't leFt him take her valuable warriors away because of the unpredictable threat of King Harald attacking their home. In spite of her words, Floki is still able to assemble a group of true believers in secret that he convinces will be happier if they make the journey with him to this new island. He also has words with Ubbe and tells him that he wants no part in this battle of brother vs. brother that is sure to be destructive to their people.
Now in Africa, Bjorn Ironsides and Halfdan, led by Kassia and Commander Euphemius, finally meet up with Ziyadat Allah and are welcomed into his camp. Allah is a very confident man and says he wants to open trading with Bjorn because he knows the Viking people have many useful things they can provide. But something happens overnight and the next day Bjorn and Halfdan learn that Allah has found Euphemius guilty of trying to betray him and ended his life. And as a Shakespearian twist, he cooked Euphemius' body and made him the feast for dinner that night, although he didn't mention this until his guests had already finished their meal. This is one man not to cross that's for sure. But things are also about to take a bad turn for our Vikings as well as Kassia has somehow turned Allah against Bjorn and Halfdan and they end up on their knees with swords aimed at their necks. Just as she is ordering Allah's men to strike, the gods might be looking out for them on this day because in the distance they can see a sandstorm coming straight for the camp and this might give them the opportunity to save their lives. But we're left with our nerves frazzled on this one because that's all we get as this History Channel episode comes to a close.