A former classmate of Haruhi's named Arai shows up in Karuizawa, and Hikaru gets jealous of her paying attention to him, feeling that Haruhi is a part of the Host Club world now. Haruhi chastises Hikaru for being rude, and later Kaoru also chastises him for throwing his feelings at Haruhi so immaturely.
Kaoru concocts a plan where he sends a fixed-up Haruhi on a date with Hikaru, hoping that it will broaden his horizons a bit. Unfortunately, after a mostly pleasant (and Haruhi-led) date, the weather starts to turn bad and they get ready to head back to the retreat. They bump into Arai, who offers them a ride, and Hikaru stomps off in a cab instead, leaving Haruhi alone.
When Hikaru talks to the Host Club via cell phone, Tamaki informs him angrily that Haruhi is scared of thunder, and thunder has just started roaring. Hikaru stops the cab and runs around trying to find her, which he eventually does, hiding under an altar in a church. He covers her with the altar cloth and puts his headphones on her so she can block out the noise, apologizing to her repeatedly.
The next day, Arai brings some watermelon to the retreat, and Hikaru apologizes to him for his behavior.