Kaito has been summoned into another world as a hero, and though all goes well for a time, one day his entire party betrays and mercilessly kills him. So when he suddenly gets a chance to redo his life, starting from the point he was first summoned to this world, he swears to exact vengeance on everyone who stabbed him in the back...

Spurred by the memories of his betrayal in his past life, Kaito continues his pursuit to exact revenge on the adventurers who killed him. When he encounters Eumis, the sorcerer mastermind behind the betrayal, Kaito's quest for vengeance kicks into high gear.

The next target on Kaito's quest for vengeance is Grond the merchant, a money-hungry villain who goes as far as murder to satisfy his greed. But when Kaito finally gets Grond in his clutches, he forces the corrupt magnate to make an impossible choice: Would he rather part with his money or his life?

Sights set on their next target, Kaito, Minnalis, and Shuria travel to the city of Kabanheim, where they find Minnalis's traitorous childhood friends leading carefree lives. But soon the partners in crime come across someone not even Kaito could have predicted-a woman named Leone who was also summoned from Earth. Still possessed of her morals, Leone attempts to interfere with their rampage of revenge...but there's no stopping Minnalis from exacting vengeance on the people who doomed her to slavery and caused the death of her mother.

Metalia ambushes Kaito just after he completes his latest feat of vengeance, forcing him through a portal back to present-day Japan. Stripped of his memories, Kaito comes to terms with his tragic new reality—a world where almost everyone he knows is dead and the police surveil him around the clock on suspicion of committing a heinous crime. Even this fragile status quo is disrupted when an assassin nearly succeeds in taking his life. But the brush with death restores Kaito of his memories and powers, giving him the perfect opportunity to take revenge on his assailant and chart a course back to his partners in crime…

Summoned to a fantasy world as a hero, Kaito Utage defeats the Demon Lord alongside a band of noble adventurers...only to be double crossed and brutally murdered by his former allies! But when a twist of fate gives him a second chance at life with his all his memories intact, he sets off on a quest to slaughter his traitorous party members one by one. "Come...let vengeance commence!"

Kaito's quest for vengeance is no longer a solo affair-with Minnalis at his side, he can accomplish so much more. As their hatred burns bright, the two of them begin their training to fulfill their lust for revenge...

The next target on Kaito's quest for revenge is Eumis, a twisted sorceress for whom no avenue of magical tool development was too immoral. But mere reprisal isn't enough for Kaito. To hit Eumis where it hurts, he turns the sorceress's own sister against her...