夜中 やちゅう
yachū

Noun
Adverb

1. during the night; at night

その ばん つぎ とその夜中 よなかずっと地下 ちか しつ ごしたのよ。
sono banto tsugino hito sono yonaka zutto chikashitsude sugoshitanoyo.
We spent all of that night, the next day, and the next night in the cellar.