A princess embarks on an adventure to gather a group of gentlemen who can take the despots of power and regain the freedom of the kingdom.

When Gilthunder spiking his sword in the center of town and stops brewing, Meliodas is the one who can remove it and turns on the local hero.

Meliodas, Hawk and Elizabeth go to a haunted forest where Meliodas faces great dangers in search of information.

Golgius tries to recover the sword of Elizabeth and Meliodas. The sound of a mysterious bell causes infighting in the group.

As Meliodas and Diane still fight each other under Ruin's control, Friesia attacks the shepherd boy that Ruin disguised himself as to prompt Elizabeth to risk her life to protect him. However, as Ruin reveals his true identity and attacks Elizabeth, he realizes she took his bell and has broken his spell as he and Friesia are quickly defeated, while the other shepherd reveals where Sennett is being held. At the same time, Ban dispatches Jude before finding Meliodas as his group rescues Sennett. Outside the prison, Golgius erects a barrier to keep them inside, but the Holy Knights retreat when the prison gets destroyed by Meliodas and Ban's destructive reunion. The group returns to Dalmally, finding Dana having somehow survived as he treats the Sins to a meal. Meanwhile, Gillthunder visits King, bearer of the Grizzly's Sin of Sloth, and reminds him of their arrangement.

Years before joining the Seven Deadly Sins, Ban sought to become immortal by drinking the Fountain of Youth, a liquid sap produced by the Fairy King's Forest's Sacred Tree, so he can live long enough for something good to happen. He ceases his attempts after learning the Fountain of Youth sustains the Fairy King's Forest, the fountain's sworn protector Elaine realizing him not to be like the other humans. In the present, Meliodas and his group arrive to a rundown town near the Capital of the Dead where King is said to be buried. Ban takes a walk, meeting Ellen and Luigi, a pair of siblings. Ban is then attacked by a strange boy who he later learns to be King, who accuses him of destroying the Fairy King's Forest while seeking to enter the Capital of the Dead himself. The siblings reveal to Meliodas's group that the Capital is another world that can only be entered when one shares a priceless memory with the dead. Ban's memory of Elaine gives the group passage, with King following after them. Upon their departure, a female Holy Knight appears in the town soon after, violently interrogating Ellen and Luigi into entering the Capital of the Dead. She then acupunctures herself into a half-lifeless state.

King easily defeats Guila with his Sacred Treasure, the Spirit Spear Chastiefol, sending her soul back into her unconscious body which the group tie up upon their return to the living world. King explains to Elizabeth and Hawk that the Deadly Sins each use their full potential with a Sacred Treasure weapon, his comrades admitting having lost theirs through different circumstances, also revealing that Guila is a type of Holy Knight from a newly spawned Holy Knight order known as the New Generation. Meanwhile, Jericho and Twigo are summoned by Grandmaster Holy Knight Hendrickson to become part of the New Generation, which acquires them to drink the blood from the corpse of the demon that ravaged the Fairy King's Forest. Twigo explodes after drinking the blood while Jericho survives the excruciating experience. The following day, with Diane and Elizabeth staying behind, Meliodas brings Ban and King to the merchant town of Vaizel and sign up for its annual fighting festival, with the prize being Diane's Sacred Treasure, the War Hammer Gideon. Holy Knights Griamore, Princess Veronica Liones' bodyguard, and Howzer also sign up.

King easily defeats Guila with his Sacred Treasure, the Spirit Spear Chastiefol, sending her soul back into her unconscious body which the group tie up upon their return to the living world. King explains to Elizabeth and Hawk that the Deadly Sins each use their full potential with a Sacred Treasure weapon, his comrades admitting having lost theirs through different circumstances, also revealing that Guila is a type of Holy Knight from a newly spawned Holy Knight order known as the New Generation. Meanwhile, Jericho and Twigo are summoned by Grandmaster Holy Knight Hendrickson to become part of the New Generation, which acquires them to drink the blood from the corpse of the demon that ravaged the Fairy King's Forest. Twigo explodes after drinking the blood while Jericho survives the excruciating experience. The following day, with Diane and Elizabeth staying behind, Meliodas brings Ban and King to the merchant town of Vaizel and sign up for its annual fighting festival, with the prize being Diane's Sacred Treasure, the War Hammer Gideon. Holy Knights Griamore, Princess Veronica Liones' bodyguard, and Howzer also sign up.

The fighting festival commences with Love Helm as the referee as eight contestants - Meliodas, Ban, King, three-time champ Taizoo, Griamore, Howzer, the town drunkard Cain Barzard, and mysterious fighter Matrona - are left standing after the elimination round. The first quarterfinal match has Matrona knocking Griamore out of the ring. Matrona is exposed as a human-sized Diane wearing Elizabeth's clothing, revealing that the two got themselves shrunk by a giant mushroom called a Chicken-Matango while foraging for food. After Howzer defeats Taizoo with one punch, King easily loses to Cain as he is nearly powerless unarmed. The fourth match is Meliodas versus Ban, with Griamore and Veronica revealing to Howzer the Seven Deadly Sins infiltrated the tournament as they search the village for Elizabeth, while Howzer rushes back to witness the fight.

Meliodas and Ban begin their match, proving to be equally skilled until Ban takes advantage of his Physical Hunt ability to steal Meliodas' strength and finish him off. However, the captain unleashes the mysterious power he exhibited in Dalmally to send Ban flying out of the ring, taking the win. The semifinals commence with Diane fighting Howzer, who initially holds back as a gentleman before going all out. Diane defeats the Holy Knight, who expresses enjoying his bout with a Deadly Sin member. Meliodas then faces Cain, who is revealed to be a former Holy Knight as he attacks Meliodas to see if he truly was responsible for the destruction of the Danafall kingdom as the rumors say. Cain makes peace with Meliodas after he confirms it to be a lie, forfeiting the match in response. The final match between Meliodas and Diane occurs soon after, with Ban making the fight more interesting by using Hawk's earnings to bribe women into provoking Diane to go all out in another jealous rage. Meanwhile, Guila and Jericho are approaching Vaizel, the latter intent on taking her revenge against Ban.

Meliodas and Diane stop fighting when they and the other Deadly Sins sense Guila and Jericho approaching, the four attempting to drive the townsfolk out by feigning a hostile takeover before the Holy Knights attack Vaizel. Jericho, who has embraced her womanhood following her defeat to Ban in Baste Prison, exacts her revenge on him before joining Guila in overpowering Meliodas before King intervenes. But Guila and Jericho are saved at the last second when Love Helm reveals himself as the former's commander Helbram, an old enemy of King's. Hawk and Elizabeth use the distraction to get Ban and Meliodas to safety, when Elizabeth returns to her original size just as Veronica and Griamore find her. Veronica scolds Elizabeth for getting herself involved with the Deadly Sins and believes Meliodas bewitched her as she traps him within a Goddess Amber, a stone specifically made to seal evil entities. Griamore is forced to trap Elizabeth when she attempts to flee with Meliodas's sword and the Goddess Amber, only to redirect the spell on Guila and Jericho when they attempt to take the girl against Veronica's wishes. Veronica chases after Elizabeth, only to take the full brunt of an explosive trap Guila littered around the village to save her younger sister. After Veronica seemingly dies from her wounds, Meliodas breaks out of the Goddess Amber in response to Elizabeth's anguished cries, but is enveloped by a dark, sinister aura.