From publisher blurb:
Under the Temple Crypt is the first in a series of site-based, Swords & Wizardry compatible, “micro modules” that can be dropped into just about any campaign (especially a sandbox-style campaign). No underlying story-hook or rational for exploring the site is given here. This dungeon assumes that there is a temple somewhere with a mysterious walled-in doorframe in the basement crypt. The walled-in doorframe predates the temple itself and leads to ancient subterranean structures that hint of an older civilization as well as an expansive underworld.
There is mention of an ancient “god of war” as well as a strange goblin deity, both of which are left purposefully vague so that the referee may further develop these elements to suit their individual campaign.