The latest Fallout 4 mod comes from a surprising source: graphics card manufacturer Nvidia. The mod, Vault 1080, upgrades Fallout 4’s visuals and adds a creepy new quest line.

Vault 1080 was developed by Nvidia LightSpeed Studios, an internal team that has focused primarily on remastering and remaking classic PC games for Android (and specifically, Nvidia Shield devices).

The mod uses Nvidia’s horizon-based ambient occlusion plus (HBAO+) technology to deliver volumetric lighting (such as god rays) and shadows that are more realistic than in standard Fallout 4. Other graphics upgrades include weapon debris and new materials.

Vault 1080’s visuals are more than mere eye candy, according to Nvidia — they’re key to the content of the mod. In the hourlong quest that Vault 1080 adds to Fallout 4, players will head through a marsh to a church that obscures the entrance to the titular vault and its dark tunnels.

Here’s more from Nvidia on the vault:

It’s certainly taken its toll on its occupants. They’ve become a congregation that embraces the darkness and sickness, and they’ve done it — so they believe — to survive. They’re not the friendliest bunch. But is the whole thing built on lies? The truth is deep within Vault 1080, through a whole lot of fearful mystery. Find it and decide for yourself whether the monsters deserve their salvation… or not.

Vault 1080 is coming this Friday, Sept. 2, for the Windows PC version of Fallout 4.

Correction: The Vault 1080 mod isn’t available yet; it will be released during PAX West on Friday, Sept. 2.