Yi Xiaochuan finds a tiger pendant by coincidence and the pendant sears a mark onto his chest when he wears it on his neck. Meanwhile, Xiaochuan's older brother, Yi Dachuan, discovers a 2,000-year-old treasure box at an excavation site. Xiaochuan unlocks the box using his pendant and opens a time portal by accident. Unknown to everyone else, he is transported back in time to the Qin Dynasty together with Gao Yao, his girlfriend's brother.
Back in history, Xiaochuan meets the historical figures Xiang Yu and Liu Bang, and becomes sworn brothers with them. He encounters the Qin general Meng Tian, who mistakes him for his long-lost younger brother Meng Yi, because the mark of the pendant belongs only to members of the Meng clan. Xiaochuan also meets Princess Yushu of Tu'an, who becomes the new love of his life. However, the lovers are unable to be together, as Yushu has become Qin Shi Huang's concubine in exchange for peace between the Qin Empire and Tu'an. Xiaochuan is unwilling to give up and he meets Yushu in secret inside the palace.