From the publishers blurb:
Welcome to an infernal dungeon run by fiends!
The devils are trying to tip the scales of the Blood War by establishing soul conversion facilities. These terrifying prisons are used to torment souls with an intention of creating more powerful devils and filling the battlegrounds of Avernus with powerful soldiers. Only brave adventurers can disrupt this horrifying scheme.
The supplement includes:
• Lore about how hell prisons are established and function.
• Advice for the Dungeon Master how to run adventures within a hell prison, including a ready made 3-level dungeon for characters level 5-10.
• 19 detailed chambers for use in the hell prison or to be dropped into existing dungeons.
• 3 new monsters - Hell Warden, Infernal Cook and a Steam Elemental.
If you are curious about the quality of the product, check out the free supplement - The Abbot Reimagined.