While escorting a supply convoy to an off base communications site north of Bagram Airbase Afghanistan, Master Sergeant George Mavrakis and his team are ambushed by the Taliban. Running for their lives with the few survivors of the ambush they manage to flee to an underground mine, but are trapped inside when a Taliban suicide bomber blows himself up in the entrance, sealing them inside. Traveling deeper into the mine they discover an underground base left there by the Soviets. While exploring the base they find a control room filled with computers and equipment which activated after generator power was restored and a countdown is automatically started.
When the countdown reaches zero George and his team of fifteen survivors are all immobilized by a strange force and rendered unconscious. Waking up they disconnect the computers to avoid a repeat. They travel deeper into the mine and eventually find a way out. When George and his team reemerge outside they realize they have been somehow transported thousands of miles from Afghanistan. While trying to discover where they are, they soon attacked by cavalry soldiers wearing medieval armor. Upon making contact with the locals they discover that they have been not only transported thousands of miles but also 560 years in the past, to the lands of what remained of the once great Byzantine empire, to the year 1451 just one year before the city is conquered and sacked by the Ottoman Turks
George and his band of 15 survivors, make contact with a Byzantine cavalry patrol that escorts them to Constantinople the capital of the once great empire. Upon arrival they are presented to the emperor Constantine the XI. George explains who they are and the future fate of the city. The emperor sees their arrival as the miracle everyone had been praying for. George offers to assist the Byzantines in improving their military and defenses. He is promoted to general and becomes the emperor's military advisor while his team embraces Constantinopolis as their new home.
The arrival of George and his troops have drastically altered the timeline. The Ottoman Sultan Mehmet II will soon put the city under siege with over 80,000 troops and 60 huge guns that can tear down the city's walls. In the American's past time line, the Ottomans do capture the city and the emperor is killed in battle. It will be race against time to assist the Byzantines in building up their technical and military capabilities with the skills and knowledge, they brought back from the future, to stop the Ottomans. If they are unsuccessful the future is very bleak for George and his team, whom are lost in time.