When Vikings returns, the History drama will begin a whole new era, expanding beyond just the saga of Ragnar Lothbrok (Travis Fimmel) to encompass the journeys of his five sons as well.

"We know that the historical Ragnar's greatest fear was that his sons might become more famous than he was. In fact, at least historically speaking, at least two of the sons did," creator Michael Hirst tells TVGuide.com. That's why the remaining 10 episodes of Vikings' supersized fourth season will not only chronicle Ragnar's attempt to reestablish his legacy, but also follow each of his sons as they attempt to build their own.

To find out what's next for Ragnar, Bjorn (Alexander Ludwig) and the rest of the Lothbrok family, check out everything to expect of Season 4B below.

Gustaf Skarsgard and Travis Fimmel, Vikings Photo: Jonathan Hession/History

Ragnar: Approximately six years following his defeat in Paris, Ragnar returns home to a changed world. The once small farming town is now a bustling city, and his sons have grown from children into young men. But the biggest change is that those who once worshipped Ragnar and thought of him as a god now despise him after learning the truth about the destruction of the Wessex settlement.

Vikings: Rollo returns to his Viking roots - but at what price?

"It just throws everything up in the air again," Hirst says of Ragnar's return. "[Ragnar's] closest allies - Floki (Gustaf Skarsgard), Lagertha (Katheryn Winnick) and people - have their own agendas now. It's a rude awakening for them and they have to balance their feelings towards him with the general feeling of betrayal that a lot of people feel, including the sons."

The love of his sons is part of what brings Ragnar back, but his reappearance in Kattegatt inspires mixed feelings in his family, who are more interested in forging their own paths than following his. That's why most of Ragnar's sons refuse to join Ragnar as he returns to Wessex to confront King Ecbert (Linus Roache), leaving his crippled son Ivar as Ragnar's only ally on this dangerous new journey.

Alyssa Sutherland and Kathryn Winnick, Vikings Photo: Bernard Walsh

Lagertha: Every time Lagertha sees Ragnar, it's a painful reminder of everything she lost when Aslaug (Alyssa Sutherland) showed up with her and Ragnar's unborn child. And so it's fitting that Ragnar resurfaces to see Lagertha one last time before she finally makes her move to reclaim her home.

Lagertha will launch a full-blown attack on Aslaug this season, which essentially means an attack on Kattegatt. But she won't have to do this alone. Lagertha will have Astrid by her side, a confident young woman and her latest lover — although Hirst is hesitant to label Lagertha as gay or bisexual. Instead, Hirst says Lagertha's relationship with Astrid is founded on her feelings of security around women, as opposed to being sexually attracted to them. "All the men [Lagertha's] been involved with have betrayed her or let her down, so she's now in a relationship with someone she feels more comfortable with and feels that she can trust," he explains.

Alexander Ludwig, Vikings Photo: Bernard Walsh/History

Bjorn: One of the few sons who's happy to see Ragnar back in Kattegatt, Bjorn's joy is short-lived once the Seer warns that he'll soon be cursing the day his father returned. But Bjorn refuses to let this dark knowledge distract him from following through on his plans to sail the Mediterranean.

With Floki and Helga by his side, Bjorn sets off to lead his first major expedition. However, in order to reach his destination, Bjorn must sail past the Frankish coast, and thus, he must gain Rollo's (Clive Standen) permission if he wants to proceed without bloodshed.

"[Rollo] has the ability [and] the fleet to stop Bjorn from [achieving] his dream, so of course Bjorn is prepared at least to compromise," Hirst says. "But Bjorn is still angry because his uncle tried to kill his father. He tried to kill his mother in that great battle scene on the river in Paris."

Unfortunately, Rollo's leverage over Bjorn is too powerful to deny, which is why Bjorn ultimately accepts his uncle's compromise: Bjorn and his crew may sail through the Frankish territory, but only if Rollo goes with them. But ever his father's son, Bjorn knows when to roll over and play dead — and when to get his revenge. So just because Bjorn agrees to sail with Rollo, don't believe that means he's agreed to forgive him.

Clive Standen, Vikings Photo: Bernard Walsh/History

Rollo: Finally out from under his brother's shadow, Rollo has settled into his new life as a duke, a husband and a father of three. Yet despite gaining everything he desired, Rollo realizes that his new life hasn't made him forget his old.

"He's gone on this wonderful, huge journey. He's become someone else," Hirst says. "But what he discovers in Season 4 is you can never take the Viking out of people. Deep down in his soul, he is still a Viking and he has to deal with that."

This is why Rollo doesn't hesitate to use his leverage over Bjorn to secure a spot on his nephew's ship, much to the chagrin of his wife Gisla, who threatens that Rollo may not have a home to return to if he leaves it now. And so Rollo betrays his family once again - but this time, it's his Frankish family he turns his back on.

Whether or not he'll ever be accepted back with the Vikings or in Frankia will remain to be seen, but hopefully this season Rollo will finally figure out who he is, once and for all.

Alex Høgh Anderson, Vikings Photo: Bernard Walsh/History

Ivar (Alex Høgh Anderson): Out of all of Ragnar's sons, Ivar is the one to watch out for this season. Despite lacking the use of his legs, Ivar's pathological brutality and spiteful nature makes him a figure to be feared, even by his brothers.

"Ivar is probably the most famous Viking of all time. And it's completely ironic that the most famous Viking of all time should have been a cripple," Hirst says. "We know he had to be carried onto the battlefield. We also know he had a reputation for cruelty, even amongst the Vikings, which I think is saying something."

Yet despite Ivar's cruelty, Vikings never paints him as a completely unsympathetic character. It's clear Ivar has had to fight his entire life to be treated as equal to his brothers, and he would rather risk it all for a chance at being respected rather than accept a lifetime of being pitied.

That is why Ivar decides to follow Ragnar to Wessex - not to right any wrongs, since Ivar cares little for morality, but to learn everything he can from Ragnar so that he may become a legend in his own right.

David Lindström, Jordan Patrick Smith and Marco Islø, Vikings Photo: Bernard Walsh/History

Hvitserk (Marco Islø), Ubbe (Jordan Patrick Smith) and Sigurd (David Lindström): Ubbe, Aslaug's eldest son, is a leader among the boys and most closely resembles Ragnar when he first started out as an altruistic, intelligent young farmer. "He sees his destiny as trying to realize what his father started," Hirst explains. But rather than seek out great adventures or explore the world, Ubbe sees it as his duty to stay home and protect his mother, proving that he is far more loyal than his father ever was.

His brother Sigurd stays behind in Kattegatt as well. But where Ubbe is calm and strategic, Sigurd is more unpredictable. "I think he's slightly more crazy [than his siblings]," Hirst says. "He was left amongst the ruins of the relationship between his father and his mother, and he doesn't quite know his place in the Viking world and he wants to try and find his place."

The final brother, Hvitserk, is the only one to accompany Bjorn to the Mediterranean. And though Hvitserk and Ubbe have shared a special bond since they almost drowned as children, this season Hvitserk will distinguish himself from his brother in shocking ways.

"Hvitserk does something so unexpected, so extraordinary and aligns himself with someone so different from Ubbe that you don't understand why he's done that," says Hirst. "And a lot of the show subsequently and in seasons to come is about discovering why Hvitserk has done this and why he's not gone the way you think he's going to."

Vikings returns Wednesday at 9/8c on History.