There is little plot or character interaction in Rhem 2; the emphasis lies solely on its puzzles. Many puzzles require the player to determine his location with respect to adjacent areas or objects in order to solve it. For instance, in order to solve a puzzle it may be necessary to trace a cable through a wall between two rooms, but the path from one room to the other is circuitous.
The game opens with the player's arrival in a series of caves underneath the city of Rhem. A video greeting from another explorer, Kales, explains that the player must find an artifact hidden somewhere within the caverns, take a photograph of it, and bring the photo to Kales's brother Zetais. The player must find the artifact in order to unlock the train and leave Rhem.