Light Novel Volume 10/Synopsis

Prologue: The Spirit Tortoise's Barrier
Naofumi and his party transported back to the previous world, and just as they arrived, the Spirit Tortoise's energy they retrieved dissolved into the atmosphere. Naturally, as a foreign entity, Raph-chan power-ups has been reset and the other's level went back to normal. The queen of Melromarc arrived aboard a carriage and along with the soldiers, gave a saltatory bow. After a brief conversation, Naofumi and co. boarded a carriage and headed for the castle.

Chapter 1: The Seven Star Staff Hero
Naifumi found out that the time in Kizuna's world passed differently from Rapthalia's world. Arrived at Melromarc, Naofumi talks about the countdown for the next Wave and various things regarding the other world and its heroes. Naofumi suggests the Queen to muster the Seven Star and Holy Heroes' power and knowledge to handle the Waves. The Queen only accepted to gather the Seven Star Heroes due to the three Heroes has fled. Naofumi and the Queen also discussed about the aftermath of the Spirit Tortoise's battle and its effect to the coalition army. Naofumi then asked the Queen for a territory to build a private army to fight the Waves. The Seaetto territory is chosen by Naofumi, and the he is given the title of Count by the Queen. After the ceremony, the Queen introduces Trash as one of the Seven Star Heroes. Due to his refusal to cooperate, the Queen planned to torture Trash to reveal his way of power-up.

Chapter 9: Hanging Out the Shield
Naofumi went peddling to sell medicines. The slave trader informed that some of the village's former inhabitants are likely at Zeltoble. Naofumi set out to Zeltoble with Filo and Raph-chan.

Chapter 10: Zeltoble
Naofumi arrived at Zeltoble and visit an underground slave market. After the Slave Trader explaining the situation regarding the slave price, they went to an auction site. Bewildered by the price, Naofumi planning to earn money by participating on the Coliseum.

Chapter 11: Slave Hunters
Naofumi and the party went back to Seaetto and find out that the village is under attack by slave hunters. Raphtalia and Keel, with aid of Naofumi, defeated the hunter boss. The rest of the hunters then immediately defeated. To amass a large amount of money for the wager in the Coliseum, Naofumi sold the captured hunters to Siltvelt.

Chapter 12: The Department Store
Naofumi asked about the tournament and ordered the Slave Trader to register him with Raphtalia and Filo in the team tournament. Because there are an upcoming match and an auction is held at the same time, Naofumi ordered Raphtalia to observe the auction while he went to observe a match later. Naofumi and co. went to a department store to look at weapons and armors where he met the accessory dealer back from his peddling days. Proceeding to the weapon and armory section, Naofumi and Raphtalia copied a few shields and katanas they don't have. No weapon or armor was worth buying there, so they went back to the underground slave market.

Chapter 13: The Underground Coliseum
By himself, Naofumi takes a peek at the coliseum battle. A drinking contest has happened near the fight. The winner of the drinking contest, Nadia, approached Naofumi and predicted the outcome of a coliseum fight. The fight ended as Nadia has predicted. Naofumi assumed that Nadia is familiar with the Coliseum, asked her various things about it.

Chapter 14: Ring Name
Naofumi and the party used an alias and wearing masks for the tournament to avoid attention. The first match is started, the opponent team is Topak Family, Naofumi's team won swiftly. The second match is against a team solely made of three monsters and again won swiftly. After the matches, Naofumi sent Filo back to Seatto, Raphtalia is sent to monitor the Lurolona slave auction winners. Rishia and Raph-chan are gathering information regarding coliseum fighters.

Chapter 15: Surprise Attacks and Conspiracies
Naofumi headed back to the tavern where he met Nadia and surprisingly she noticed that Naofumi was participated in the tournament, despite the effort to hide his identity. Nadia brings Naofumi for a night stroll but they are ambushed by mercenaries. Nadia defeated the mercenaries swiftly and pointed out that these ambushes was the reason why some participants didn't appear in the tournament. Nadia told Naofumi to give up if they happened to fight in the tournament, then they went separate ways. After gathering information regarding the participants, Rishia reported that Nadia is an opponent they should wary of.

Chapter 16: Nadia
Due to the increased opponent's absence, Naofumi won by default for the next several days and reached the semifinals against Nadia. Nadia fought so well, even capable of canceling Naofumi's Aura buff and bested Raph. The arena then altered by the spectators to Nadia's favor. The spectator's interference made the fight went back and forth but in the end Naofumi's party cornered Nadia. Nadia gets serious and transformed into her beast form. When Nadia preparing an attack, Raphtalia just stood in a daze. Naofumi moves to protect Raphtalia, and then she uttered "Sadeena."

Chapter 17: Farce
Nadia suddenly halted her attack. Raphtalia and Nadia conversed and recognized each other. Nadia suggests them to pretend to continue the battle while explaining each other's situation. After Raphtalia and Filo staged an apparently devastating combo, Nadia admits defeat.

Chapter 18: Exhibition Match
Right after the match, the organizers forced Naofumi and Sadeena to team up and participate in an exhibition match under heavy handicap against Murder Pierrot who isn't even participating in the current tournament. With Filo's Humming Fairy skills and Sadeena's guide to using cooperative support magic, they managed to defeat Pierrot. Everyone was surprised to find that Pierrot's body was just wood and Pierrot appeared in another body. Pierrot talking to Naofumi and the party but the voice is disturbed by crackling and static noise, leaving an order to get stronger as the only perceptible message. After the talk, Murder Pierrot disappeared with an explosion. Naofumi is declared as the winner and headed back to the waiting room.

Chapter 19: Big Shots of the Underground
Sadeena went to confront her boss with Nao, followed by Rishia, Raph-chan, Acc dealer and Slave trader. With Acc dealer and Slave trader's backing, Nao proposed a deal to put Sadeena's bet to the next match so her previous contract can go on. In the next match, which is a throwaway, to begin with, Nao easily won.

Epilogue: Come-On
Naofumi obtained fifteen slaves and bring them to the village. Dialogues between Naofumi and the villagers, including Sadeena's attempt to claim him due to her defeat in a drinking contest.