While no video game is perfect, Valve’s puzzle-based masterpiece Portal 2 comes pretty darn close. In fact, Portal 2’s near-perfection is probably one of the reasons why Valve never made another official Portal game, because how could you top a game like that? Well, one solution would be to simply make a story-driven unofficial expansion that builds on what made Portal 2 so great, and that’s exactly what one group of fan modders is doing with their mod Destroyed Aperture.

Technically, Destroyed Aperture has been in development since 2015, but the group behind the mod recently updated its ModDB page with an announcement saying that the mod’s mapping process is now roughly 95 percent done, and that a trailer for the mod should be arriving either towards the end of or a little after summer, 2018.

The announcement also clarifies that a release date for Destroyed Aperture mod hasn’t been nailed down yet, but an FAQ page over at the mod’s official website points to a fall, 2018 estimated release window. As for the scope of the mod, it will feature a new story campaign that will be roughly five hours in length and will contain a total of 20 new maps and 30 new puzzles. Here’s a synopsis of the mod’s story:

“Destroyed Aperture is a free community made modification for Portal 2. You take the role of a man named David that gets woken up in an overgrown and decayed Aperture Science Facility 7. Facility 7’s central core has failed and destroyed any and every communication systems along with the environment and killed almost everyone. The facility has been in a decayed state for years, locking everyone in. But not all hope is lost, there’s still is a chance of escaping.”

Once it’s released, Destroyed Aperture will be free to download and play. A copy of Portal 2 will be required to run the mod, but you won’t actually need to have it installed on your computer, it just needs to be in your Steam library.

For more on the latest sci-fi gaming coverage, be sure to read about the upcoming (and free) game Mobile Suit Gundam: Battle Operation 2 and the new 1.06 patch for Detroit: Become Human.