The episode begins with the aftermath of the group's confrontation with Ai's betrothed god. Yayoi explains that the balance of power among the spirits in her room has been disrupted, leading to a "devouring," where weaker spirits are consumed by stronger ones. During this time, a new, more powerful spirit, known as a "Graduate," is born.

Yayoi and Keitaro receive a mysterious phone call, which Yayoi warns Keitaro not to answer. She explains that the spirits have grown so powerful that their influence can spread up to five houses away from their home. To counter this, Yayoi decides they must capture more spirits and strengthen their defenses.

The group gathers to discuss their new plan. Yayoi reveals that they must not only defeat the "Ghost of Death" that kidnapped her mother but also capture Ai's betrothed god to save her from her fate. To do this, they need at least six "Graduate"-level spirits. Yayoi displays a map of haunted locations across Japan, each marked with an estimated danger level, where they can capture these spirits.

Yayoi and Keitaro then go on a bike ride, during which Yayoi admits she is happy to have Keitaro as her partner in this fight. She takes him to an unmarked, dangerous haunted site known as "Castle H Ruins," an S-rank danger zone. Yayoi sees this as the perfect opportunity to capture a new "Graduate"-level spirit, especially since Eiko is not home and thus safe from spiritual disturbances.

The episode ends with Yayoi and Keitaro preparing to enter the ruins of Castle H, setting the stage for a perilous adventure where they will gather the strength needed for the battles ahead.