Tether is a first-person fantasy horror adventure. The Earth is dying after the collapse of several continents around the world following the destruction of the Moon — as natural disasters sweep the planet, the newly formed United Environmental Federation (UEF) accelerates plans to terraform the closest possible habitable planet, Mars. You play as Leslie Hayes, a UEF biological research assistant, on her first deep space journey to Mars. Once aboard the Sonne, Leslie's thoughts turn to her children as she relives some of their last conversations before leaving. As catastrophic events unfold on UEF Sonne, Leslie is forced to endure the psychological horrors of isolation in deep space.