Lily is reunited with her late mother's book after her writing lessons show promise, reclaiming a treasure that had been taken away under the pretense of preventing her from ruining precious paper. Although the orphanage staff and snooty appraisers believe the book is completely mundane and blank, Lily is the only one who can open its pages, defying their attempts to burn or force it open. Inside, the dormant soul of Arakil finally awakens from a long stasis, shocked by the low ambient mana of the current era and realizing his telepathy is broken and his memories are fractured. He resolves to gather what little mana he can to become operational, observing the rhythmic motions of the girl writing on his pages as his only hope for survival. As Lily begins to practice her writing and drawing in the book, she is unaware that she is communicating with a sealed god of magic who will soon teach her the secrets of the cosmos. This quiet reversal of her fortunes begins to turn heads as she effortlessly masters complex letters and doodles, leaving her peers lagging behind. The true escalation occurs when she is accepted into the prestigious Regarth academy on a full scholarship, a feat that draws intense jealousy from high-profile students. Upon her arrival in the remote town of Kaeling, the local townsfolk give her the cold shoulder, and a helpful staff member reveals a shocking truth that was omitted from her acceptance letter. Every single prospective student must pass a grueling entrance test before entering the school proper, and failure means immediate rejection. With her tiny heart sinking and her dreams of following in her mother's footsteps on the verge of shattering, she feels the book in her pocket minutely shift in size, signaling that Arakil is ready to unleash his teachings, but will this frail Lagia girl be able to survive the dangerous trials of the dungeon?

During their first dungeon camping trip, Lily and her friends Lotte and Thomas venture deep into the second floor of the forest dungeon, a place teeming with dangerous monsters. When they are suddenly ambushed by a massive, terrifying dire bear, the team is thrown into a panic as the beast charges with unstoppable speed and power, threatening to trigger their protective Wards. Instead of fleeing, Lily decides to put her recent glyph lessons to the test, using her magical wand to swiftly draw explosive runes directly on the ground in the beast's path. She demonstrates incredible precision under pressure, swishing her wand in quick and definitive strokes while her friends distract the monster with lightning and poison magic. When the charging beast triggers the stacked runes, a terrifying blast erupts, throwing the massive bear into the air and shattering its limbs, proving that Lily's magic is far from a simple trick. Lotte follows up with a potent corrosive spell that eats away at the giant monster, allowing Thomas to deliver the finishing jolt of lightning. The victory is a massive face-slapping moment for their rivals, especially the cocky noble students who believed a frail Lagia bunny girl could never survive on the front lines of combat. Their teacher, the former four-star adventurer Alice, is left speechless by the sheer scale of the destruction and the luxurious fortress Lily constructs using temperature-stabilizing, water-generating, and shadow-shrouding glyphs. However, their celebration is cut short when they realize that the loud explosions have echoed through the dense forest, drawing the attention of even more dangerous predators lurking in the shadows. As the night watch begins and the false sun of the dungeon sets, a strange, floating purple eyeball appears at the edge of their camp, watching their every move with an ominous gaze that suggests they are being targeted by the dungeon itself, leaving them to wonder if their next battle will be their last.

When a greedy attempt to steal a rare treasure chest from a dryad's domain backfires, the ancient dungeon itself becomes vindictive and possesses the dryad to hunt Lily's team down. The possessed creature easily bypasses their camp's defensive charms, unleashing a terrifying shriek that throws Lotte and Thomas into absolute panic as they realize their Wards might not save them from this anomaly. To save his apprentice from certain doom, Arakil is forced to initiate a supreme ritual, temporarily taking control of Lily's body and revealing his divine key to the world. He puts her friends to sleep for their own safety and teleports them deep into the lower floors of the dungeon, traversing through snowy tundras, scorching deserts, and pitch-black tunnels to show the dungeon his true power. Faced with swarms of mutated ant monsters, Arakil demonstrates the pinnacle of astral magic by summoning an all-consuming black hole that devours the entire insect army in a terrifying display of void magic. He then teleports to the molten magma depths to confront the dungeon's metallic lizard avatar, using a crushing gravity spell to pin the beast to the floor and threaten its core. Faced with absolute destruction, the dungeon core is forced to negotiate, swearing on its core to cease hostilities against Lily, hide her secrets, and allow them to safely siphon its mana. This dangerous excursion successfully repairs the grimoire's archives and elevates their familiar bond, allowing Lily to communicate with Arakil telepathically without any eavesdroppers. However, as they return to the surface, Lily must quickly drag her unconscious friends back to their tents and repair the camp before they wake up, hoping they will believe the terrifying encounter was nothing but a vivid dream, but she is left holding her breath as she hears Lotte whisper about divine magic in her sleep, hinting that some secrets cannot be so easily buried.

Determined to officially unlock the second floor, Lily, Lotte, and Hana embark on a rapid speed run through the shifting maze of the first floor, racing against their strict curfew. Utilizing Lily's custom-designed crystal seeds and Hana's light magic, they quickly clear room after room as the dungeon dynamically increases the difficulty to stop their progress. They finally face the giant floor guardian, a massive skeleton king clad in heavy brassbound armor that towers over the throne room. By combining Lily's newly mastered Lunar Eclipse curse to skew probability, Hana's focused light lasers, and Lotte's corrosive acid, they successfully destroy the guardian, revealing the staircase to the second floor. This historic victory makes them the first first-years to officially conquer the first floor, earning them praise from Alice and Headmaster Fabrelis. However, as they prepare for the upcoming school festival, Lily realizes she must gather public belief in her glyph magic to break through the restrictions of reality and draw without a wand. She begins drawing beautiful, functional glyphs around the school grounds, sparking rumors of a legendary new bloodline that draw the attention of the powerful Mustelia clan, who hold a monopoly on crystal magic. With the alchemy competition commencing and the headmaster introducing standardized glyph ink, Lily stands before a massive audience, ready to prove her skills, but as she stares at the mysterious ingredients of the final test, she realizes the recipe is a trap designed to expose her secrets. She must now navigate the intense rivalry between noble families while keeping her connection to a sealed god hidden, knowing that a single misstep on this grand stage could draw the wrath of royal inquisitors and ruin everything she has worked so hard to build. As the countdown reaches zero and the identical flames erupt under the cauldrons, Lily freezes as she notices a dark, shifting energy within her ingredients, signaling that someone has sabotaged her station to force her to fail in front of the entire kingdom.