Subject 67 regains awareness inside a puzzle chamber, quickly learning he is a human-demon hybrid—the product of Loremaster's experimental series, officially subject 67 in the 66th batch of the 6th experiment, though Lucifer points out that the subject in that slot actually died the day before. Loremaster dismisses the discrepancy and continues running her experiments.
Working through increasingly complex puzzles, Subject 67 advances under Loremaster's commentary. She eventually reveals herself as an angel wearing a demon disguise—though Lucifer mocks this, noting that Loremaster still reacts like an infatuated teenager whenever anything suggestive appears. The dynamic between them is openly combative. Subject 67 is hostile throughout, threatening to take everything from Loremaster. She responds by offering apple pie instead of her best girl, and he accepts.
The final challenge is a massive robot modeled after the skeleton guards. Subject 67 defeats it. Loremaster, delighted, commissions a fresh batch of apple pie from her baker Justice. Afterward, Lucifer dresses Subject 67 in a suit over his protests and lays out her real agenda: because Loremaster knows so little about how Subject 67 works, he could be valuable in helping Lucifer reclaim her crown and reassert control over Hell. She tells him to think about it—adding that he reminds her of someone she once knew.