"Added to the collection is an all-new fifth adventure -- A0: Danger at Darkshelf Quarry -- that you can use to kick off an AD&D campaign that pits a group of adventurers against the evil Slave Lords! Module A0, designed for levels 1-3, sets the stage for events that unfold throughout the remainder of the "A" series."
Darkshelf Quarry, eh? Great. I was on the fence about buying this book but now I'm too curious to pass it up. Anyhow, no word yet on who the head writer is on this intro-module. I'm personally hoping for Chris Perkins who has shown to have a good knowledge of the setting, having done reworks of the Giants series including a whole new episode for that epic as well.
Stay tuned for more information on this in the near future (Thanks again).
Update 05/08/2021: You can get A0 in this book on DMsGuild.