Hostile Atmosphere is one of the many side quests in Once Human that have you complete a series of small tasks outside of the main story. It can be a bit tricky to get started, but everything becomes clear quickly.

When you receive the Hostile Atmosphere quest while in the Chalk Peak region, you can expect to encounter several challenging enemies along the way. You'll attempt to figure out what's going on with the disturbing Stardust readings in the area and how they're connected in Once Human.

When you receive the Hostile Atmosphere quest in Once Human, you will need to head to a convenience store that is located far north of the Tall Grass Inn settlement. You should find it before you reach Holt Town. While you are in the convenience store, you will need to search the area for the next step. To activate the next step, look for the Rosetta Researcher standing next to the Stardust device and speak to him. When you first reach this area, you will not be given a direct path to this NPC. You will need to search to the west of the convenience store to find them.

You need to talk to the researcher to proceed to the next steps of the quest. They will tell you that they are conducting experiments on Stardust using the device. However, the experiment was not what they had hoped for and they need your help to destroy these devices. Once you agree, you will need to track down the other devices in the Chalk Peak region in Once Human to complete the quest. The first of these three is in front of you.