In Halo 4, John-117 returns as the protagonist after three Halo games focusing on different characters. Having been lost in space in the finale of Halo 3, John-117 and Cortana, adrift aboard the wreckage of UNSC Forward Unto Dawn, find themselves near Requiem, the planet first seen in the Legendary ending of Halo 3. When John-117 accidentally releases the Ur-Didact, an ancient Forerunner plotting to have all humans either imprisoned or destroyed, John's mission becomes stopping the Ur-Didact.