: They target a woman named Blair, believing her to be a witch. However, after a series of comedic and intense battles, it is revealed that Blair is actually a magical cat with multiple lives, not a true witch.

: Because they consumed a cat's soul instead of a witch's, Lord Death confiscates all 99 of their previously collected souls as a penalty, forcing them to start their quest from zero. Character Dynamics and Themes Episode 1 | Soul Eater Wiki | Fandom

The episode is structured around the final stages of the duo's initial soul-hunting quest:

: With 99 Kishin souls collected, they seek a witch's soul to complete Soul's transformation.