“It’s time,” she thinks, “to sing our back-to-school song”

1984 cover

as follows:

I don’t seem to be able to upload the subtitles as part of the video, but this ensemble is North Korea’s Moranbong Band and the song it’s singing is titled, in the Korean jussive mood, “Let’s study.” Here’s a PDF of the subtitle file.

North Korean Moranbong Band 배우자 – Let’s study (English Translation) [VDownloader]