In the year 2164, a wormhole into an alternate realm was opened by accident, and malevolent creatures known as "replicators" have emerged from there. A bitter war was fought, but the replicators had overwhelming numerical superiority. They managed to replicate the entire Earth, and a suicide mission was sent to destroy this alternate Earth with an energy bomb, by reaching as deep as possible into its core. However, the heroes were unable to reach the core, and were forced to engage their alternate plan - detonate the bomb at the wormhole in hope of closing it.

When they came to, they found they had crashed landed on Earth, more specifically in China of the year 241 BC, right in the middle of a battle where five kingdoms have united to challenge the dominant Qin nation. Upon seeing the survivors in their mecha suits, they regarded them as gods, and fled in fear. The twelve people from the future have turned into the Great Qin Warriors, helping the ruler of the country to conquer the entire China, found the Qin dynasty, and become the First Emperor. But the price to pay for this glory is too high - the twelve heroes must find a way to return to their own time and save the Earth.

Great Qin Warriors is a mecha-type first-person shooter. The single-player mode is mission-based; the player selects available missions, which take him to various exotic locations of different regions and time periods. A multiplayer mode is available as well.