Though he has successfully repelled the latest Wave of Catastrophe, Naofumi Iwatani—the Shield Hero—has no time to rest. Naofumi is spurred back into action when Queen Mirelia Q Melromarc tells him that the three other Cardinal Heroes have disappeared without a trace, and she tasks him with finding them. With no clues regarding their whereabouts, Naofumi tackles a more pressing issue: the worsening slave trade of demi-humans. Determined to right this injustice, he and his friends find their way to Zeltoble, the country of mercenaries, where the illegal sale of demi-humans has become a lucrative business. To gather money to free the slaves, Naofumi and his comrades disguise themselves and take part in underground coliseum brawls, purposely throwing matches to manipulate the odds and eventually secure an enormous payout. However, with the threat of another Wave of Catastrophe looming on the horizon, the Shield Hero must stick to his mission of finding the missing heroes if he wants to protect those he loves.

In the harsh region known as the borderlands, humans must fight an endless battle against demi-human creatures that come at them relentlessly, intent on taking their land and their gods. A young boy named Kai, fighting to defend his village, sustains a life-threatening injury that causes him to regain memories from a past life. If you're not a guardian bearer, it's like you're playing life on hard mode... Kai's newfound knowledge gives him a new sense of the unfair rule set that governs the world around him. One thing is clear: For those without a god to serve as their guardian, life is a constant struggle for survival. Thus begins the epic tale of a young boy's ascent into a vast world filled with magic, bloodshed, and mystery. (Source: J-Novel Club)

Following the success of Shiny Colors' first concert, Mano Sakuragi and her friends continue to face new challenges. After Straylight, a new unit of 283 Production, makes its debut concert, the members of the units are temporarily shuffled into new groups to prepare for a Halloween event to help them grow individually as idols. While Mano struggles to express her ideas, her fellow unit member Hiori Kazano feels left out by her new comrades' talent. At the same time, Fuyuko Mayuzumi, who has bitterly failed to become Straylight's center, proves completely unable to show her real personality, jeopardizing the entire project in the process. Shiny Colors' producer will have to find a way for Fuyuko to break out of her shell if he wants to see his idol units illuminate the world once more.

Ever since moving into his own apartment, quiet high school student Kei has been looking for a new thrill. He soon finds himself playing mahjong, but his whole life takes a dramatic turn when he is forced to play the game with a criminal group. Even though the odds seem against him, Kei is able to outmatch the others. Instead of claiming his reward in cash, however, he decides to take an abducted girl named Amina under his wing. Due to Kei's skills and cold playstyle, the mysterious Hideharu Seki takes an interest in him, introducing him to mahjong parlors and new potential opponents. But when matched up against an experienced player named Doujima, Kei is severely outskilled and only narrowly escapes going into serious debt. If he wants to protect his new life with Amina, Kei must find a way to outwit these shady characters and come out on top in every game he plays.