From Destinypedia, the Destiny wiki
Dread Patrol is a story mission in Destiny The Taken King. It takes place on the Dreadnaught as part of the Quest The Vanguard's Hand. It is only playable once by the same Guardian, and it unlocks the Dreadnaught as an open Patrol area. 
All dialogue is spoken through the Ghost's comms.
A waypoint appears for the Guardian, on a ledge very high above the floor. The Guardian makes the climb and surveys the impressive view of the battle between three species: Cabal versus the Hive and the Taken. Enough information is soon collected.
The Guardian heads to the Mausoleum, and plants a beacon underneath the bridge leading to the Rupture. As before, the signal starts to broadcast to the Guardian.
The Guardian starts running as several blue markers appear on their HUD. The energy reading steadily depletes in between bursts of concentrated energy, but as they run through enough spikes, their findings come to a head.
The Guardian continues onto the next area, the Hall of Souls. Finding a suitable place for the beacon, they plant it into the floor.
The Guardian makes their way through, eventually finding themselves back in the Trenchway where they first crash-landed. Several Taken blights appear, spawning numerous forces. The Guardian eliminates them all, but the objective updates as a Taken Ultra arrives in their place. The Guardian continues fighting Balvog, Shield of Oryx, until it eventually falls dead.