The original developers of Roller Coaster Tycoon 3 are suing their former publisher for substantial royalties.

Frontier Developments is an independent studio, largely made up of the developers of Roller Coaster Tycoon 3. Since their departure from publisher Atari, they have been responsible for the epic space-faring sim Elite: Dangerous and the spiritual successor to the aforementioned theme park simulator with Planet Coaster.

Frontier claims that it received $1.17 million in royalties from Atari for the third iteration of the Roller Coaster Tycoon franchise in a contract amended after Atari filed for bankruptcy in 2013. Recently, they have allegedly uncovered information from an unspecified online source that has led them to believe that Atari shorted them by a whopping $2.2 million.

So far, Frontier Developments has remained relatively tight-lipped about the details of the case. According to COO David Walsh:

We can confirm Frontier is currently pursuing a complaint against Atari. We have attempted to resolve this issue without legal action since April 2016. We have so far been denied our contractual right to audit by Atari, and we are unfortunately left with no other way to resolve our concerns. We are unable to offer any further comment while the matter is subject to due legal process.

It isn’t the first time Frontier and Atari have met in court. In 2007, Atari sued Chris Sawyer for allegedly aiding the team in an attempt to sell an “enhanced version” of Roller Coaster Tycoon 3 to another publisher. As it happens, Atari doesn’t even own the Roller Coaster Tycoon IP — they’re licensing it from its creator, Chris Sawyer. That case was settled out of court.

Nevertheless, this and the comparative success of Planet Coaster to Atari’s recent mobile Roller Coaster Tycoon World train-wreck, means there is probably very little love lost between the parties.

Follow Nate Church @Get2Church on Twitter for the latest news in gaming and technology, and snarky opinions on both.