Long ago in a distant land, Aku the shape-shifting master of darkness unleashed an unspeakable evil, but a brave samurai warrior wielding a magic sword stepped forth to oppose him. Before the final blow was struck, Aku threw open a portal in time and flung the samurai into the future, where Aku's evil is law. Now the samurai seeks to return to the past and undo the future that is Aku.

This show is a reinvention of the long-running series of the same name that was canceled in 1989. It begins with the Ninth Doctor. The Doctor is an ancient Time Lord/Lady. The Doctor travels through time and space with their T.A.R.D.I.S. (Time and Relative Dimension in Space). The Doctor is accompanied by companions on adventures. They will encounter some monsters, but at times, they also have to save the world.

After the earth was destroyed by a nuclear war, the remaining people put together a giant space station called the "Ark" into space to survive. Then after 97 years of living in space the counsel sends the 100 juvenile prisoners down to earth. Once they arrive, they are quick to set a "no law" system of government. The 100 realize they are not the only ones on earth and they quickly adapt to their new home.

In a world where humans can bend the four elements, water, earth, fire, and air, the ruthless Fire Nation has engaged the rest of the world in a war that has lasted one hundred years. The world's only hope is the Avatar, the only one who can master all four elements. When the Avatar returns one hundred years later, a young Airbender named Aang, it's up to him to defeat the Fire Nation, and bring balance to the world.