In the futuristic world of Project Eden, cities that have run out of room expanding outwards instead must build upwards. The game is set a city that has been built to the sky, layer upon layer. The very bottom of the city, the actual ground level, is never seen by most citizens and many assume it to be deserted, if they think of it at all. The ground is given very little concern by most folks, actually, aside from the occasional team of engineers that must head down to the Earth's surface to reinforce base structures and building foundations.
Now, one of these teams of structural technicians has traveled below and has not returned. Guiding team members of an elite government force, the player must follow the missing engineers to the depths of the planet's surface and investigate. Project Eden features four characters for the player to control, each with unique skills and personalities. Players can switch from several different camera angles and move between a first- and third-person perspective. As the characters descend lower and lower into the city's depths, conditions become more dangerous and strange. Cultists, criminals, and worse make their homes in the bowels of the city. The heroes will be well challenged just to survive the trip.