In the future world, the stupid human civilization makes the earth's environment worse, and the warm and sweet hometown becomes a purgatory full of disasters and death. After that, humans traveled through space to build a new home on the first star, and the monster Ursa controlled by aliens launched a brutal massacre on this group of outsiders. The supreme commander of the Rangers, Sefer Rich (Will Smith), known as the "original ghost", led his men to effectively stop the enemy's slaughter. Although it is said that a tiger father has no dog son, Sefer's son Kitai (Jaden Smith) failed the Ranger test. Rich, who had a gap in his heart, set off for the Ifitus training base, but unexpectedly, he was forced to land on the familiar and unfamiliar earth due to an accident on the way. The violent collision almost killed all the crew members, and Rich and his son became the only survivors. With his father seriously injured, Kitai could only go alone to find the signal machine for survival. For this child who never grows up, he will face the most important test in his life...