Kiera Cameron and the mysterious time traveler, Brad Tonkin must battle the Future Soldiers who arrived in a flash of light in the last moments of season three. Meanwhile, Kiera's alliance with the remaining members of Liber8 challenges her relationship with both Carlos and Alec Sadler. Kiera must also face off against Kellog, who is using every option available to him to become the ruler of a dark future built in his image.