Korso (voiced by Bill Pullman) and Preed (voiced by Nathan Lane) are revealed to be in league with the Drej. Korso wanted to find the Titan ship so he could hand it over to the Drej in exchange for a large sum of money, believing that humanity had no chance of survival. Cale (voiced by Matt Damon) and Akima (voiced by Drew Barrymore) escape them, and using a different ship from a human drifter colony base they manage to find and access the Titan.
Cale gets a pre-recorded hologram message from his deceased father Sam (voiced by Ron Perlman) who tells Cale that the Titan has the power to create a planet, and the ring he gave him would've activated the transformation sequence. However, the power cells in the ship needed for the sequence had no power left, brought on by the ship's escape from the old Earth before the Drej demolished it. Without power, the transformation sequence can't start.
Korso and Preed then show up, but Preed double-crosses Korso, saying that the Drej agreed to allow him to live if he killed everyone else before they arrived to destroy the Titan. Korso kills Preed, and almost succeeds in getting away with Cale's ring, but Cale fights him and Korso falls off a ledge and vanishes from his sight. Korso grabs onto a cable as he falls, saving himself from death.
Cale realizes that if he could reroute the system of the Titan to use Drej energy, it would start the reactor, and the relays are linked to three circuit breakers. The first two connect, but the third jams up. As he makes his way to the area to fix it, Korso re-appears, where he has a change of heart and aids Cale to help him get to the circuit breaker.
In the end, Korso sacrifices himself to bridge the circuit breaker, and the Drej mothership shoots a destructive energy beam into the ship as Cale places his ring on the control panel and begins the transformation sequence. The ship proceeds to drain the Drej of all of their energy through the beam and destroy them. The Titan forms a new Earth for the human race (which Cale calls "Bob") and the last scenes show Cale and Akima on the surface of the new planet and the human drifter colonies arriving to make their new homes.