Couran's army prepares to battle Thomas, unaware of the bombs in the forest. As Charlotte and her mages prepare to fire, a suspicious Rosell stops them and instead has them launch a fireball over Thomas's army to distract them as Braham, Clamant, and Fahm ambush the enemy soldiers. Thomas charges at Couran, but Ars tries to take him on instead. Ritsu comes to his aid and manages to defeat Thomas, but only temporally. Eventually, Thomas's forces are beaten as Mirelle approaches her brother while Ritsu scolds Ars for his recklessness. Mirelle explains to Thomas that it was Rosell who saw through his plan, not her. After using his evolved appraisal skill, Ars convinces Mirelle to express her true thoughts to Thomas: she is impressed, but also pleased that he managed to finally outsmart her for the first time. In turn, Thomas surrenders and is taken to prison as he is still loyal to Vasmarque. This allows Couran to capture the last of the enemy territory. Ruper is appointed as a new headman for one of the captured districts, while Ars is given his own district to rule. However, some of the servants are doubtful as they believe Ars is too young for the job, but Krall and Hammond come to his defense, along with Ars's allies. That night, Ars speaks with Lumeire regarding their success. The next day, Ars visits Lysia and receives a warm welcome from the villagers. Lysia and Ars's family all come out to greet him. A wedding ceremony is then held for Ars and Lysia.

A flashback reveals Mirelle and Thomas's childhood. When they were kids, Mirelle always had the advantage over Thomas, which tore their relationship apart as Thomas strived to outsmart his sister. During adulthood, Mirelle was banished from the enemy domain and Thomas began serving its lord. Returning to the present, Vasmarque figures that Mirelle has allied with Couran's army, but still considers Thomas a faithful ally as they make it their goal to kill Couran. Meanwhile, Couran speaks with Ars's group regarding his confrontation with Thomas. He is then approached by a messenger who requests a truce from one of the enemy lords, but also reveals a large deadly weapon that can instantly destroy surrounding areas for miles. Ars and his allies suspect this to be a trick. Another flashback reveals that Mirelle and Thomas's father was murdered after he was branded a traitor and allows for his children to be murdered too due to their dangerous capabilities, although they were instead thrown out into the streets and eventually became strategists; Mirelle shares her backstory with the rest of Ars's group at Rosell's urging. Thomas prepares for his next attack against Couran's army and hopes to defeat Mirelle. Once Couran and the others learn that the weapon has been spotted, Ars sends Fahm to investigate and he discovers that it is fake. The truce offer was just a ploy to buy more time to strengthen the main enemy base. Recalling the mock battle from before, they deduce that Thomas's plan was to get close without attracting attention. However, Thomas had known that they would figure out his decoy plan and send their soldiers into the forest that he is hiding in, having installed explosive devices that will detonate when they come in contact with flames, thereby wiping out Couran's forces instead. However, he again intends to make sacrifices to ensure their success, which worries the enemy soldiers. Thomas then recalls more of his past, which includes his loyalty to Vasmarque. Despite the risk, all the soldiers choose to stay with Thomas, agreeing to sacrifice themselves to win the war just as Couran's army arrives at the forest.

Ars and his friends continue to the enemy castle. Charlotte uses her magic to deflect oncoming flaming arrows and open a way inside. As the battle carries on, Ars's forces are slowly winning, forcing the enemy soldiers to surrender. Braham, the red-haired warrior from the previous episode, appears and attacks both Ritsu and the enemy soldiers after they insult him. Ritsu manages to defeat Braham due to the latter relying more on brute strength than intelligence. After Ars reads Braham with his powers, Braham asks for Ritsu to be his teacher, who reluctantly agrees as Ars allows Braham to join his team. Mirelle then forces the enemy soldiers to reveal their traps and troop positions in the castle and Clamant helps disable the traps, allowing Ars's forces to conquer it, forcing its lord to flee. Couran is grateful that Ars helped to take down the enemy territories, but is curious about Ars's power after he reveals it to Couran. Later, Ars and his friends get into a snowball fight along with other activates. Fahm disappears to avoid the wrath of an angry crowd as a result of them wanting their money back after betting over which team will win the snowball fight as a result of it ending in a draw. Meanwhile, Thomas, frustrated that his sister has been thwarting his every moves, is confronted by Vasmarque.

Following Rolto's defeat and capture, Fahm is unhappy that his payment didn't meet his demands, so Ars promises to fix it. Fahm returns to camp, but finds it attacked. In another enemy castle, it is revealed that Thomas is responsible for the attack, to which he intends to weaken Ars's forces by destroying their supplies. Thomas explains to the castle's lord that he plans to target Couran himself. Ars and his subordinates deduce Thomas's involvement in the ambush and Mirelle sends Fahm to help Couran as it begins to rain, which is actually a spell that Thomas's forces will use for magic attacks. Thomas ambushes Couran, but Fahm rescues him with his shadow magic. Thomas chases after them, but Fahm hinders him with his magic. Though Thomas manages to defend himself against Fahm's attacks, he is forced to retreat upon learning that Couran is long gone. Though Couran intends to pay Shadow for their help, they decline it as it was Ars who hired them in the first place. Recalling his past, Fahm returns to Ars and offers to be his retainer, to which Ars accepts. Meanwhile, back at the enemy castle, a red-haired warrior wielding a heavy axe that only he can use prepares to make his move.

Ars and his army continue to run from the enemy forces while Shadow hides from Jean's men, forcing them to take another route, but Ruper's wife goes into labor. They manage to narrowly avoid being spotted by the guards. Meanwhile, Ars's army has made it to the forest, but they figure that Jean was aware of their ploy. Jean decides to return to the castle as he knows of the trap that Ars has arranged, but most of his men disobey him and go after Ars's army. When Dan also decides to go after Ars, Jean is left no choice but to follow, but they are unaware that Mireille is disguised as one of the enemy soldiers as part of her and Rosell's earlier plan. They meet up with Clamant's men, who are prepared to face Jean's forces. The enemy soldiers are easily defeated while Mireille and Charlotte reunite with Ars. Dan manages to get through Clamant's forces, and Ritsu fights him one on one. Ritsu is overwhelmed, but manages to outsmart and defeat Dan. Jean arrives, but Clamant easily defeats him. As a result, the enemy soldiers are forced to surrender. Upset by his defeat, Dan attempts to commit suicide, but is stopped by Jean, who still considers him a faithful ally before they are taken prisoner. However, Ruper begins to die from his wound, but he miraculously recovers when his wife arrives along with Fahm and her newborn baby. Ruper is reunited with his wife and child. A funeral is held for the soldiers who died in battle. While celebrating their victory, Ars laments losing his soldiers during war and he and Ritsu send letters to the dead soldiers' families.

Ars and his subordinates begin their plan to rescue Ruper's wife. A warrior named Clamant Maitraw then arrives to help. He is the leader of a company consisting of combat mercenaries that Ritsu knows of. However, Clamant is neutral in the situation and only works for money, but is nevertheless willing to aid them. The rescue plan is then put into motion. Meanwhile, at Castle Rolto, Lord Jean assumes that he is on the verge of victory. He receives a blood-stained letter from Ruper (who forged it on Ars's orders) warning them that Ars's forces are targeting Rolto and that a mage is helping them. The next day, the battle between Ars and Rolto's army begins. Dan, the leader of the enemy army, proves to be a strong fighter. Fahm rescues the hostages from Rolto before they can be transferred. At this point, Ars's army retreats with the enemy soldiers in pursuit, but Jean discovers that the retreat is a ruse and joins the fight. Flashbacks reveals that Jean killed Dan's father to become a noble. Dan and Jean catch up with Ars's army and easily kill the soldiers. Deciding not to ask Clamant for help, Ars opts to continue with their original plan despite it backfiring. Dan surprises Ars, but Ritsu saves him and fights off Dan. Enemy soldiers appear in front of Ars, but they attack the other enemy soldiers instead of Ars's army. They are actually Ruper and his soldiers, who have come to help. As the enemy soldiers fall back, Dan shoots Ruper with an arrow in retaliation for his betrayal, but he survives. Rolto is now aware of Ruper's treason and Dan orders the hostages to be killed, but discovers that they have escaped and, realizing that there are spies in the castle, initiates a manhunt for them.

Lysia is pleased to learn that Ars has succeeded in conquering one of the enemy castles. The army decides to rest for a while before resuming the war. While out shopping, Ars buys a wind up toy egg with a small mechanical bird. As they prepare to take over the remaining two enemy castles, Ars learns that Ruper Louston, a lord from one of the enemy castles, is requesting a negotiation. He, Ritsu, and Mirelle head there, but are greeted with hostility. Under Mirelle's advice, Ars makes everyone drop their weapons and they are allowed in. After Ars drops the toy egg, it releases the mechanical bird, which flies around the room; this causes Ruper to develop a change of emotion. The negotiation is discovered to be a trap, but Ars, after reading Ruper with his powers, learns that he is being blackmailed into helping Vasmarque and that his pregnant wife is being held hostage in the other enemy castle. Ars then makes a deal: he will rescue Ruper's wife and in exchange, he will ally with Ars's army. Despite the dangers of doing this, Ruper agrees.

Thomas and Vandol learn of Fort Vakmarko's defeat. After Ars's forces capture the enemy soldiers, Couran plans to kill them due to it not being wise to keep them alive, including Selena. Against this, Ars attempts to convince Couran not to. Following Rosell's advice, they then get the idea to spare those who are willing to help them while using those who refuse to as hostages. Selena is skeptical of allying with Ars due to her status as a lord, but after a talk with Charlotte, she is sent to ask if her father is willing to join too. That night, Fahm arrives with news: Castle Samkh has stronger defenses and warns them about Thomas. After Selena returns to her father, she expects to be punished for her failure, but he is grateful that she's alright. The next day, Ars begins his attack on Castle Samkh and manages to get past an indestructible gate with the help of Fahm and his men. The hostage exchange forces the castle's troops to surrender. A flashback then reveals that Selena was unhappy when Vandol's personality changed upon entering the war, which led her to also join. Thomas plans to use explosion magic to ensure their victory by pretending to surrender so to lure Ars's forces into the castle so he can trigger the trap, though it will require sacrificing those that are also in the castle. Unwilling to murder innocent people, they refuse the plan and destroy the detonator, defecting from Vasmarque's army. A soldier attacks them in retaliation, and although Selena tries to protect her father, he manages to step in and stop them. They then decide to join Ars's army after being spared from punishment. Meanwhile, Thomas, although displeased with Vandol and Selena's betrayal, reveals to have another detonator and activates the castle bombs to wipe out Ars's army, but the explosion happens in a different location, rendering it completely harmless. It turns out Fahm secretly moved the explosives beforehand due to Rosell suspecting something off about the attack. Although he is upset for putting Fahm in danger and not telling Ars about this earlier, Mirelle cheers him up. With Selena and Vandol now part of their group, they continue the war against Vasmarque.

While approaching the enemy territory, Ars grows nervous, but his subordinates support him. They prepare to launch an attack on one of the enemy bases, but are surprised when the enemy suddenly surrenders seeing that they are outnumbered. Meanwhile, at Castle Samkh, Vasmarque's right-hand man Thomas Grangeon (Mirelle's younger brother), who possesses great strength, prepares to make his next move against Ars's forces with Fraedor, Vandol and her daughter Selena, who is also a mage. Ars forms a plan to take control of the three fortresses surrounding Castle Samkh. They start their attack on the first fortress: Fort Vakmarko. Selena creates a forcefield around the fortress while Charlotte and her mages attempt to break through it, with some difficulties due to the forcefield's self-repairing magic. After discovering that powerful enemy forces are behind them, making retreat not possible, Ars has Ritsu lead an army to deal with them. He manages to defeat the enemy soldiers with ease. When Selena boosts her magic on the forcefield, Charlotte decides to use all the magic that she and the other mages have despite the risk of doing this. Charlotte's magic eventually overpowers Selena's and destroys the forcefield, but this wears her out. The group then continue their plan to take the fortresses and Castle Samkh.

Lysia reveals that Lenge exposing the truth was also part of her plan to bribe the minister. Lenge believes that using trickery to their advantage is wrong. However, when Lumiere tells Lenge that what Ars and Lysia did was necessary because they are not at the same level as him, he comes around realizing that he was the fool and decides to help Lysia after all. They eventually complete their negotiations with Paradille with Lenge's help. After returning to the Couran's castle, they inform Couran of their progress, but he is displeased with Lenge for joining Ars without letting him know and for his foolish actions. He then rewards Ars with a large amount of gold. When Ars grows fearful of the upcoming war, Charlotte promises to support him, with Lysia also promising to help too. Ars returns home and reunites with his subordinates. While shopping with Lysia, the villagers grow worried about Ars and provide him with a large supply of food. Ars visits his father's grave along with his subordinates to give their blessings to him. The next day, while Lysia remains behind to watch the estate, Ars and Couran prepare for battle against the enemy with a large army of soldiers and Ars's subordinates.

After becoming engaged to Lysia, Ars explains his plan to negotiate with the minister to his subordinates. Charlotte expresses further jealousy of Lysia's engagement to Ars, but he requests for her to be their escort. As the group travel to the Paradille kingdom, they meet up with Fahm, who provides them with vital information on the enemy nation, who has joined forces with another nation. Ars discovers that Lysia has kept textbooks with her as a sign of their love. They later meet Couran's son Lenge, who displays great pride. Ars reads his abilities and tells Couran about it. Ars, Charlotte and Lysia later go shopping before boarding a ship. Lenge also joins the group on their mission. They rescue some men along the way, but they are revealed to be pirates who try to take their valuables using Charlotte as a hostage, but she overpowers them. However, they learn that the pirates are actually fishermen who are poor and their families are living in poverty. Ars decides to loan them some money despite Lenge wanting to punish them instead. They reach the capital, but see how some people are rich and some are poor. The next day, Lysia wears a pretty dress as they visit the minister. Through a plan that Lysia thought of earlier, she bargains with the minister and nearly succeeds, but Lenge ruins it at the last second with his arrogance and unwillingness to lie. Having also planned for this, Lysia offers her dress and jewelry to the minister, which he accepts and finally agrees to ally, but is somewhat cautious of Couran due to Lenge's behavior. Everyone is pleased that the negotiations were successful.

The episode begins with a recap of the first season. Ars and his subordinates are on their way to see Lord Couran. Along the way, they stop at a beach, but are forced to leave after disturbing the owner. After arriving at Couran's castle, Couran's subordinates are highly doubtful of Ars's group, especially Mirelle, but Couran is very supportive of them. They then discuss a plan to deal with the enemy forces with Mirelle and Rosell's help. After their scheme is put in motion, Ars visits Lysia for advice on the war. As Ars and Lysia spend time with each other and after they confess their feelings, they both ask each other to marry. Everyone is shocked to hear that, but nevertheless approve of their decision. Fahm delivers information on the imperial family as Ars forms a plan to win over the minister.