GR translation: next night

[Mike Jing]

V353.26-32, P358.35-41   There is a crisis over which kind of g to use in
the word “stenography.” There is a lot of emotional attachment to the word
around here. Tchitcherine one morning finds all the pencils in his
conference room have mysteriously vanished. In revenge, he and Radnichny
sneak in Blobadjian’s conference room next night with hacksaws, files and
torches, and reform the alphabet on his typewriter. It is some fun in the
morning.

Which night does "next night" refer to exactly? Is it the night immediately
following the day Tchitcherine found the pencils missing, or the day after?