APEX: A time-travel experiment in which a robot probe is sent from the year 2073 to the year 1973 goes terribly wrong thrusting one of the project scientists, a man named Nicholas Sinclair into a plague ravaged alternate time-line whose war weary inhabitants are locked in a constant battle with killer robots which are automatically being sent there from Sinclairs lab. To escape this situation, Sinclair must find a similar time machine in this alternate world and prevent the disaster from ever happening.