In The Planar Gateway, a group of level-3 characters hears of a device that is capable of opening a portal in the fabric of reality to gain access to other planes of existence. An elvish mage managed this portal until decades ago when he disappeared and the portal was decommissioned. Now, several parties want to reopen the portal for selfish reasons. The characters are hired to do it.
When they arrive, they encounter a decrepit compound and the unstable portal apparatus. They must find out how it works and how to operate it strange machinery to open it. Once they do, they are sure to learn why the elf mage closed it off and what are the strange extraplanar threats that await them should they choose to explore the worlds beyond the veil: the other planes of existence.

This is a low-level Shadowdark adventure that has the heroes explore an arcane compound, find out ways to operate derelict elvish machinery, and fight a strange creature that threatens to cross over to the Material Plane.

This adventure has been designed for Shadowdark RPG through their 3rd party license. The system is meant to be accessible to OSR players and modern players alike. Adapting the material to 5e or other systems should not be difficult.
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