Summer Break Spent with a Vampire Episode 7

As Akari's summer break has finally begun, she wracks her brain to come up with fun, summery things she can do together with Sophie. However, the ocean or anything outside are all a bad fit for a vampire like Sophie. Then she has a moment of clarity and realized that a firework festival is at night and a summery activity, so she immediately begins preparing yukata. Erie and Hinata and join them to go to the festival, however...