Among the many other games that came out on Steam last Friday was a title called The Sinking City. In normal circumstances, it wouldn’t have stood out. It’s a game from 2019 that earned mostly average reviews. However, its developer, a studio named Frogwares, says The Sinking City was uploaded to Valve’s storefront by its previous publisher without its consent.

On Monday, the studio shared a lengthy blog post and video detailing its allegations against Nacon. In short, Frogwares claims the company purchased a copy of the game from a competing storefront and then went on to hack and upload it to Steam. The developer said this is Nacon’s third attempt to publish a pirated version of The Sinking City and this latest one came after the company issued it a 48-hour ultimatum. According to the studio, the Steam release of the game features several telltale signs that had it been altered, including missing logos and UI elements. Frogwares was able to examine the config files using its own encryption key, which it appears Nacon didn’t change when it reuploaded the game.

“To be clear this is hacking and when hacking has the purpose to steal a product and make money with it, it’s called piracy or counterfeiting,” the studio said. “In order to achieve this goal, programmers with serious skills need to be involved. This is not DIY work by inexperienced people, this is done by programmers who know [the] Unreal engine well.”

The two companies have been involved in litigation over The Sinking City since 2019. That’s left the game unavailable on some platforms. The studio believes Nacon will attempt to publish the hacked version of The Sinking City to other storefronts. Nacon addressed the allegations in an update on the game’s steam page. “We regret that Frogwares persists in disrupting the release of the Sinking City. It was Frogwares who came to Nacon to request financing for the development of the game, and to date, more than 10 million euros have been paid to Frogwares by Nacon,” it said.

As of the writing of this article, The Sinking City is still available to buy through Steam. Frogwares said Nacon will have to face “legal consequences” for its actions.