The hot, hot summer of Tajimi has arrived, and Himeno, Mika, Naoko, and Touko have a blast in the river trying to catch eel!
Then suddenly a kappa appears before them and takes them down to Ryūgū-jō.
Inside Ryūgū-jō, a certain person in the form of their high school self is awaiting them...
It's fine! It's always so nice 
and cool and empty in here!
لا داعي، المكان بارد ومنعش وفارغ
!هنا دوماً! إنّه الأروع
Nicht doch, das hier ist sowieso das beste Plätzchen,
nie was los und immer so angenehm kühl.
C’est rien, voyons.
Si figuri! Questo posto è sempre
 bello fresco e vuoto, è perfetto!
Imagina! Aqui é sempre
tão fresquinho e vazio!
Не за что. Здесь всегда так
приятно, прохладно и пусто!