Alternative universe where the Soviets launched a massive attack in the mid 80s. Initial NATO defensive lines are crushed. NATO sacrifices a small unit of rat tag defenders to slow down a Soviet spearhead so NATO can setup a better situated defensive position. You are this desperate unit, where you will most likely die. You are piloting, one of two M1A2 prototype tanks at time of the invasion for trials.
Fun defensive mission, lots of casualties, don't look for historically modeled units, look for a large desperate battle instead.
The mission ends when you decide it does.