The "Agents of Change" DLC for Splash Damage's Brink was detailed a while back, and is now available to download on your dashboard or through xbox.com.
The battle spreads to two all-new districts of the Ark – the futuristic, underwater Labs facility and Founders’ Tower, the iconic spire housing the island’s elite. Unleash new abilities on your enemies and customize your character with new outfits and weapon attachments. Brink™ Agents of Change downloaded with this version of BRINK requires the most recent title update. If the update is not present, the DLC will not be available for use. Please update the game by launching BRINK while connected to Xbox LIVE.
"Agents of Change" is free for the next two weeks, so take advantage now whether you own Brink already or plan to play it anytime in the future.
We've got the full list of Brink achievements - check the list for guides to unlocking them.