The alien race known as Necris is still fighting against the humans but when they attack the Twin Souls mining colony, they made a big mistake because it was the hometown of James "Reaper" Hawkins. He now seeks revenge together with his sister Sarah and his team mates Terrence Marshall and Jeremiah O'Connor. To get it over with they join the Izanagi Corporation where they get transferred into a special ops division lead by none other than long time tournament champion Malcolm.

In the single-player campaign you take control over Reaper and fight in closed matches in the different available gameplay-modes against the Necris and other enemies of the Corporation. To convince your enemies that they are wrong, you will find the usual arsenal of known Unreal Tournament-weapons scattered around the map. These include the humiliating impact hammer, the Trident Tri-barrel Rocket Launcher and the devastating Redeemer. The famous Translocator is also back again to allow you fast movement around the maps. But it's not the only means of transportation in Unreal Tournament III.

Like in Unreal Tournament 2004 many maps also feature vehicles like the Axon Goliath or the Necris Darkwalker. In addition to that you also have at all time access to the new Hoverboard which allows you to travel fast but you can't use any weapons at the same time.There's also game-mode called Vehicle CTF where the different machines are essential in winning the round.