For years the Garde have fought the Mogadorians in secret, but now the invasion has begun. John is on the front lines in New York City. The odds are against him, but his best friend, Sam, has just inexplicably developed a Legacy--and he isn't the only one. As the pair tracks down Five and Nine amidst the chaos, they meet another teen with powers. But is she a friend or foe? Meanwhile, Six, Marina, and Adam are trapped in Mexico. They got into the Sanctuary and were able to awaken the force hidden within, but they don't have any way to contact the others...and the Mogs are coming for them in full force. The Garde are stretched thin. Their only shot at saving the world is to eliminate the Mogadorian leader--but his fate is now irrevocably tied with Ella's. They can't destroy one without the other. And if the Garde can't find another way to stop the Mogs, humanity will suffer the same fate as the Loric: annihilation.