Gideon returned to Ravnica seeking help after discovering that courage and invulnerability could not protect a world from a titan. Jace agreed to accompany him. They arrived too late to save Sea Gate from its first fall, but helped survivors escape and began connecting forces that had been fighting separate defeats.
Nissa had lost contact with Zendikar’s soul as destruction spread. Guided toward the Khalni Heart, she restored that bond and recovered the ability to call on the plane’s elementals and leylines. The renewal made her essential to any plan using the hedrons, while also drawing the attention of Ob Nixilis.
Zendikari forces retook Sea Gate with help from Gideon, Jace, Nissa, Kiora and commanders who had survived the earlier disaster. The victory was real but temporary. Ulamog approached the city, forcing the defenders to decide whether reclaimed ground was a symbol worth holding or another place from which civilians had to escape.