The World's Strongest Rearguard: Labyrinth Country's Novice Seeker

When the Rearguard awakes, he finds himself in a strange space filled with people lining up in a queue. A guide hands him a token called a "Seeker's Token" as she says, "Welcome to the Labyrinth Country." In this otherworld known as the Labyrinth Country, Arihito, now a novice seeker, sets out with Theresia, a Lizardwoman mercenary, to tackle their first labyrinth, known as the "Field of Dawn."

Kyouka, Arihito's younger boss, is under attack by a monster. Her opponent is a powerful Named Monster called Redface. Kyouka bravely takes up the challenge, but the enemy's attack hits her head-on! Arihito rushes in to help, but his skills as a Rearguard are unable to support Kyouka, who isn't part of his party. "Run away, Atobe..." Kyouka says this as she lies on the brink of death.

Misaki, Suzuna's best friend, falls into a trap inside the labyrinth. To rescue Misaki, Arihito and his party decide to team up with Suzuna and Elitia. But then Elitia says, "If I told you to run, then leave me behind and run..." It seems Elitia is hiding a secret?! Meanwhile, Misaki is being attacked by a Named Monster, the Juggernaut!

I... want to turn Theresia back into a human, Arihito tells his companions. Having learned that the key to undoing the transformation lies in District 4, the group resolves to press on past District 8. Afterwards, Arihito and the others take a brief rest at an inn. Arihito is enjoying the large public bath, which they have all to themselves, when suddenly...

Having obtained a treasure chest known as the Black Box, Arihito and his party head to a workshop called the Chest Cracker to unlock it. "Welcome to Arthur's Chest Cracker." There, they met Palme, the female proprietor of the workshop, and Shion, a massive guard dog of the Silver Hound breed.

Arihito and his party have reached an unexplored territory where no one could normally enter. Waiting for them there is a new Named Monster: the Giant Eagle-Headed Warrior. While engaged in a fierce battle against an enemy more powerful than any they have faced before, Arihito gives precise orders to his companions.