Elsweyr is the title of a massive new expansion to The Elder Scrolls Online, due out on June 4. Fans of The Elder Scrolls universe will know it as the ancestral home of the cat-like khajiit race. It’s expected to add loads of new content to Zenimax Online Studio’s already successful MMO. To help hype that release, the enterprising team at Bethesda Netherlands created a brief pen-and-paper adventure set on the border between Cyrodiil and Elsweyr.

But that adventure appears to borrow heavily from a published Dungeons & Dragons adventure, leading to accusations of plagiarism. Bethesda has since taken down references to the module on social media while an internal investigation takes place. As originally reported by Ars Technica, the files are still available via DropBox.

The Elsweyr adventure is clearly based on the popular Dungeons & Dragons 5th edition ruleset. That’s all fine and good, of course, since D&D’s developer and publisher Wizards of the Coast has sectioned off a discrete portion of 5th edition — the Systems Reference Document (SRD) — under the Open Gaming License. That license allows anyone to create content compatible with D&D, even AAA video game studios, so long as they abide by its rules.

What the SRD doesn’t allow, however, is for plagiarism of other works published for the D&D ruleset. The work in question appears to be The Black Road, written by Paige Leitman and Ben Heisler and first published in 2016.

It’s a surreal day when a top tier gaming company steals your shit, I assure you #dnd #dndal @bethesda https://t.co/FvNvgEDKPw — Ben Heisler (@ZhentarimPR) May 8, 2019

Heisler has been vocal about the situation on Twitter, while Leitman herself went to Facebook to detail the incident. Her original post has since been removed. Other notable designers, including James Haeck (Waterdeep: Dragon Heist), have also gone to social media to clarify what appears to have happened.

The fact that they used 5th edition rules is perfectly fine, as long as they comply with the OGL. That's not the issue. — James Haeck (@jamesjhaeck) May 8, 2019

Bethesda has taken action. The company says that it is “investigat[ing] the source” of the adventure. Polygon has reached out to Bethesda, Wizards of the Coast, and Zenimax for additional comment.