I natt rømmer vi is a Norwegian children's book from 1932, written by Bernhard Stokke.
[1][2] The book is a story about two boys fleeing from a school institution for "bad children".
The model was quite obviously the institution Toftes Gave, located at the island Helgøya in the lake Mjøsa, where Stokke had served as a teacher for several years.
The two protagonists are the good friends "Harald" and "Willy", both sixteen years old.
One night they climb out through the window, find a rowing boat and successfully reach the landside.