Seven years after humanity was devastated by a major disaster, a beacon of science and prosperity rises in Kamitsubaki City. But lurking in its shadows are Tesseractor, monsters born from human darkness. Only the Witchling, five girls with voices that wield magic, stand against them. With every note, they fight, not just to protect the peace of the city, but to heal a broken world.

After a strategic maneuver, Senkuu Ishigami's team stalls Dr. Xeno's more scientifically advanced forces. A ceasefire between the two factions allows for the establishment of Corn City in North America, a hope for a future thriving population. Meanwhile, Senkuu and some of his teammates rush toward the Amazon in South America—the epicenter of the petrification beam's impact—to create Superalloy City and progress their spaceship project. With dangerous enemies still pursuing Senkuu and his companions, it is a race against time to reach the heart of the dense Amazon. As unexpected allies and scientific creations further fuel this leg of their journey, Senkuu is closer than ever to finally uncovering the mystery behind the petrification phenomenon.

Middle school student Satomi Oka ought to be proud that his choir group placed second at a national competition. However, he views this achievement as a failure caused by his inadequacies. Furthermore, since graduation is fast approaching, his time as leader of the choir is coming to an end. While Satomi is preoccupied with his inner turmoil, a smooth-talking gangster named Kyouji Narita approaches him and requests him as a singing teacher. Every year, Kyouji and his colleagues participate in a karaoke competition, where their boss personally designs a tattoo for the loser. To avoid such cruel and unusual punishment, Kyouji asks Satomi to help him find the best song suited for his vocal range. Albeit reluctantly, Satomi sets his fears aside and agrees to join Kyouji at his karaoke practice sessions. But it remains to be seen whether the mismatched duo will overcome their respective obstacles or fail miserably.

Lua is a saintess candidate who possesses the power of healing. But her ability had one flaw: she could only heal others by transferring their wounds onto herself. Because of this, others bullied her, calling her the "Fallen Saintess." But it didn't bother Lua because her best friend Arianne always stood up for her. One day, Lua's crush, Commander Garrett, was on the brink of death from a beast attack. Lua healed him, which left her on the verge of death. When she woke up, she learned that all the credit was given to Arianne, and she finally saw her best friend's true color. Devastated, Lua is lost and helpless when the second prince appears in front of her with a tempting offer. What would happen to Lua as she begins her new life as a villainess?