The October 22 premiere date has been set for the upcoming Sword Art Online -Progressive- Scherzo of Deep Night film, whose Japanese release was delayed in late August. Originally, it was scheduled to launch on September 10.

The "nationwide spread" of Covid was blamed for the postponement's production bottlenecks.

Yen Press describes the volume as:

It’s been just two months since they were trapped in the game of death that is Sword Art Online, and Kirito and Asuna continue their struggle at the vanguard of progress through the game. The fifth floor of Aincrad is a mazelike ruin, and the two dare to take pleasure in raiding it for the treasure it contains. Upon returning to the fourth floor, it’s time to do some questing on behalf of the Elf Lord Yofilis–but here begins Asuna’s discontent, for in doing so they will have to face her least favorite monster ever…

The follow-up to Sword Art Online -Progressive - Aria of a Starless Night, which debuted in Japan on October 30, 2021, is Sword Art Online -Progressive - Scherzo of Deep Night. The movies are based on the light novel series Sword Art Online Progressive, a spin-off that builds on the "Aincrad arc" of the original and still-running Sword Art Online series. The story in the fourth volume of Sword Art Online Progressive is titled Scherzo of Deep Night.

As of June 2021, there are eight volumes in the Sword Art Online Progressive light novel series, which debuted in 2012. The books are released under the Dengeki Bunko imprint of Kadokawa. Reki Kawahara wrote the main and Progressive Sword Art Online light novels, and abec did the drawings.

Since 2014, manga versions of the Sword Art Online Progressive light novels have been produced.