Dragon Age II has several main quests which have to be completed in order to complete the game.
The Destruction of Lothering
A Business Discussion
Act of Mercy
A Friend in the Guard
A New Home?
Blackpowder Promise
Enemies Among Us
Friends in Low Places
Long Way Home
Shepherding Wolves
The Deep Roads Expedition
Tranquility
Wayward Son
All That Remains
Blackpowder Courtesy
Demands of the Qun
Finding Home
Following the Qun
Offered and Lost
Prime Suspect
Profit and Loss
To Catch a Thief
Best Served Cold
On the Loose
Showdown
The Last Straw