Decided to look up the game on dtrpg.com. The physical copy is available. The softcover/softcover + pdf versions are showing a price of $16.99, and the hardcover/hardcover + pdf are showing a price of $29.99 at the time of the typing of this. I’ll let you decide what you want to do based on my quick review of the game or your past experience with Christopher Grey/Sundered Hold Scriptorium games.
Do you have a link to the Dungeoncaster game?
Here is a link to gameplay for the system. The system mechanics are effectively the same as both utilize the Caster System, though DungeonCaster renames one or two minor things. Highcaster: Oathstar - YouTube
The dtrpg link: Dungeoncaster - Sundered Hold Scriptorium | DriveThruRPG.com