As Keitaro, Naru and the Hinata residents return home to meet Grandma Hina, Haruka opts to stay with Seta at the Todai Ruins. As the groups returns to Hinata House, they discover Hina hadn't arrived.
Visiting Tokyo University, the duo receive a phone call from Hina who offers to tell Keitaro who his promise girl was. However Naru, not wishing to find out if she wasn't his promise girl, hung up the phone. Getting worried over her relationship, Naru attempts to cement her standing by taking Keitaro to a Love Hotel and engaging him in sex. However, her attempt is interrupted by Nyamo's sudden appearance.