Seth has rapidly gained more magical power, but he's gotten so used to it that his handling of magic is has grown sloppy. To teach him a lesson, Yaga forces Seth to wear gloves that prevent magic use and says that if he removes them, he'll be expelled. Meanwhile, the Bravery Quartet that Seth met in Pompo Hills is now up to no good in Artemis Academy. Seth tries to stop them, but without the use of his magic, it's a tough battle.

Ohkuma Minoru knows a lot about animals and insects, and her fascination with living things has led her to keep a research notebook of her daily observations. That fascination has now turned toward her classmate, Komichi. Komichi knows a lot about various creatures due to her country upbringing, and she takes notes on things that interest her. After learning that they have these things in common, Minoru and Komichi decide to observe their classmates together. Minoru believes that acting in secret is important when observing living things, but Komichi, the only student at the school who wears a sailor uniform, tends to stand out and isn't the best at being secretive...

Ohkuma Minoru knows a lot about animals and insects, and her fascination with living things has led her to keep a research notebook of her daily observations. That fascination has now turned toward her classmate, Komichi. Komichi knows a lot about various creatures due to her country upbringing, and she takes notes on things that interest her. After learning that they have these things in common, Minoru and Komichi decide to observe their classmates together. Minoru believes that acting in secret is important when observing living things, but Komichi, the only student at the school who wears a sailor uniform, tends to stand out and isn't the best at being secretive...

In October 1013, King Sweyn leads a fleet of Danish and Viking ships in an attempt to take London Bridge of England. Askeladd’s army, hired by the army of Denmark, was among them. However, after the betrayal of Thorkell the Tall, a Viking known for his overpowering strength, London Bridge has become impregnable. Askeladd tells Thorfinn he’ll reward him with a duel if he’s able to kill Thorkell.

After capturing the treasure from the Franks, Askeladd’s men return to the village of Gorm on the Jutland Peninsula in Denmark to pass the winter. Thorfinn challenges Askeladd to a duel as a reward for bringing him the head of the captain of the clan of Franks. Even though Thorfinn has grown in skill through his experience in battle, he is still no match for Askeladd.

Askeladd withdraws temporarily from the war against England. While searching for a new source of income, he encounters a skirmish among the Franks and hatches a plot to steal their treasure. Askeladd sends 16 years old Thorfinn, who has grown up into a cold-hearted Viking, ahead as a messenger.

Thorfinn goes to battle for the first time as a member of Askeladd’s army. After witnessing the harsh reality of the war to conquer England first-hand, Thorfinn tries to run away, but later throws himself into battle in order to get revenge for his father by defeating Askeladd. One night, Thorfinn gets wounded in battle, and is saved by a mother and daughter living in a village by the sea.

After Askeladd kills Thorfinn’s father Thors, Thorfinn hides inside Thor’s ship and bides his time until the opportunity to take revenge. However, life on the ship is harsh without any food or water, and Thorfinn grows weaker day by day. One day, Thorfinn, armed with his sword, attempt to attack Askeladd in his sleep...

Thors and his men fall for Askeladd’s trap and faces a dangerous situation, but Thors defeats many of Askeladd’s men with his overpowering strength. However, Thors knows that it will be difficult to save everyone, including his son, who’ve been living in a peaceful village their entire lives, and makes a tough decision.

Askeladd, the leader of a Viking army of a hundred men, receives orders from Floki of the Jomsvikings to kill Thors, who was once known as the Troll of Jom. However, the villagers, completely unaware of the order, buzz with excitement as they prepare for their first battle. Thorfinn also joins in the excitement. Thors and his men are about to embark on a difficult sea journey to England.

Askeladd comes forth before King Sweyn and implores him to halt his invasion of Wales. Meanwhile, Thorfinn decides to return home at Leif’s urging. However, the moment before he boards the ship, Thorfinn catches a glimpse of a single tern taking off into the sky...

After the assassination attempt on Canute’s life, rumors spread through York saying that the king is trying to kill Canute. As a result, the king is unable to issue any orders that would put Canute in harm, and Askeladd is pleased that everything is proceeding as planned. However, the tables turn when King Sweyn speaks. Meanwhile, Thorfinn is sent to prison as punishment for disturbing the peace.

Thorfinn begins his duel against Askeladd with Canute and Thorkell as witnesses. However, Thorfinn is unable to strike as he stands overwhelmed by the extraordinary mood that overtakes Askeladd after Bjorn’s departure. Having noticed Thorfinn’s hesitation, Askeladd lays down his sword and provokes Thorfinn into an unarmed fight, which incites Thorfinn’s fury.

Canute’s party arrives in York to attend the Imperial Council. Although Canute had wanted to strike out against King Sweyn, the King was being guarded by the most powerful Jomsviking unit in the Northern Sea while keeping a close eye on Canute. With the situation strained to the breaking point, Askeladd comes up with a plan. Meanwhile, Thorfinn is reunited with a person who knew his former self.

After the fighting dies down, Canute takes in Askeladd and Thorkell as his followers, and returns to Gainsborough. Canute goes through an awakening when he realizes the meaning of love in the aftermath of Ragnar’s death. Canute throws away what little feelings he had left for his father, and joins Askeladd in plotting to assassinate King Sweyn.

In the year 1002, the war between England and Denmark was intensifying. One day, the Jomsvikings pay a visit to Thorfinn’s village in order to bring back Thors, their former commander, to prepare for the impending battle. Thors is forced to join the war in order to protect the villagers from being taken hostage, and must face his accursed past in order to save his family and his village.

Thorfinn suffers a serious injury in his fight against Thorkell. Thorfinn is told to think about what he has to do to beat Thorkell. Askeladd treats Thorfinn’s wounds so that he may fight again someday, and proposes a joint strategy to help the two of them survive longer.

Thorfinn and Thorkell agree to have a duel over the fate of Askeladd. Thorkell looks forward to facing off against Thors’s son, Thorfinn, and asks him what a true warrior really is. Meanwhile, Canute is suddenly ambushed while he attempts to escape, and has a dream about a certain individual.

Askeladd’s men continued their march to escape Thorkell. However, Torgrim and his friends were hatching a plot to switch sides and join Thorkell, taking Canute with them. Torgrim finally launches his rebellion and corners Askeladd, negotiating with him to hand over Canute, then Thorkell arrives in the midst of the confusion.

Askeladd and his men are attacked by the English army in the village where they had planned to camp during the winter. Askeladd captures their captain and interrogates him to find out how the English knew where they were, and discovers that Thorkell is fast approaching. The news of Thorkell’s arrival sends waves of shock among Askeladd’s followers.