Zavala: The success of Vanguard stems from training, from gear, and most of all, from experience. Your mission to Phobos was what started this war. I can think of no one better suited to lead this assault.

The Buried City, Meridian Bay, Mars

Zavala: The tunnel system beneath the old city of Freehold is extensive. Much of it is uncharted. But, thankfully, much of it is also collapsed. This should be a standard sweep and clear. Good luck.

Tharsis Junction, Meridian Bay, Mars

Ghost: This rail system was endless. It connected colonies, dig sites. I'm even detecting a line that runs all the way up to the Cradle at the North Pole.

The Guardian enters the Black Garden.

Ghost: Temporal energy. Strands of Darkness. Vex circuitry.

Zavala: The Black Garden? We had no idea this entrance existed. Guardian, there are Vex among the Taken. They may know how to re-form the heart!

Taken appear.

Ghost: An Echo of Oryx! That explains where the Taken are coming from.

The Guardian heads further into the Black Garden.

Ghost: When we destroyed the Heart, we locked the Garden to the surface of Mars. All the Taken had to do was... walk through the front door.

The Echo of Oryx escapes into the Black Garden, Meridian Bay, Mars

Zavala: An Echo of Oryx loose in the Black Garden? The thought chills my very soul. It may have escaped, but your assault was a categoric success. We'll have teams mop up the remaining Taken and we can begin tracking that Echo.