"Vikings" Season 4 is all set to return for its 16^th episode titled "Crossings" that will mainly focus on Ragnar's first-born son, Bjorn (Alexander Ludwig).

Bjorn's fleet will continuously make an effort to keep sailing towards their destination which is supposedly the land bordering the Mediterranean. However, according to some reports, the said journey will not be smooth and that his team will have to face turmoil.

Bjorn's fleet will launch a surprise attack, as per "Vikings" Season 4 Episode 16's synopsis. The attack will be directed to whom remains to be seen, nonetheless.

The promo shows Floki (Gustaf Skarsgård) telling Harald (Peter Franzén) and Halfdan (Jasper Pääkkönen) that they will have to kill him before killing the people they meet. Consequently, Harald affirms that he wants to get rid of Bjorn, and therefore Ragnar's legacy. They'll maybe sort out their differences in the wake of their quest.

Meanwhile, viewers have seen the death of Ragnar Lothbrok (Travis Fimmel), "Vikings" main character in the TV series' 15^th episode. Fans are certainly excited to see what happens and how the remaining characters' lives change following his death.

With the central character's demise, fans apparently question who will take over his place. Lagertha, Bjorn, Floki and Rollo are the possible candidates. But Ivar is expected to be this season's main character, as per Forbes review.

Furthermore, other "Vikings" reports claim that another lead character is going to die before the current instalment ends. This is no other than Lagertha (Katheryn Winnick) who killed Aslaug (Alyssa Sutherland), the mother of Ivar, to claim power in Kattegat and who's still on the quest for more power.

Some fans are guessing that Ivar will be the one to kill her as he is coming back to revenge both of his parents' death. However, viewers still have to wait until next week to see whether Lagertha will die in the hands of Ivar.

"Vikings" Season 4 Episode 16 airs on Jan.4 at 9:00 p.m. ET which is also scheduled to air in Australia on SBS One from Jan.11 at 8:30 p.m.. Watch the upcoming episode's promo in the video below.