Rimuru decides to throw a summer festival resembling the ones held in Japan. The monsters have never experienced a summer festival, but when they hear that it's a party, they go all-in to prepare. All the monsters of Tempest work together and eventually come up with masks, paper lanterns, and even festival floats. On the day of the festival, everyone in the town enjoys piping hot takoyaki, cold shaved ice, yukata, and a Bon dance. In the end, they fill the skies with fireworks as the festival reaches its climax...
The goldfish in this alternate 
world sure are strong...
السّمك الذهبيّ في هذا العالم البديل قويّ حقّاً
Die Goldfische in dieser anderen Welt,
Los peces de colores de aquí
son muy fuertes.
Los peces de colores de aquí
son muy fuertes.
Ils sont balèzes,
les poissons rouges de ce monde !
I pesci rossi di questo mondo... 
sono davvero forti.
Os peixes-dourados deste
mundo são fortes...
Золотые рыбки в этом мире…
очень сильны!