To progress the story along you must complete enough key missions in each month to unlock a story mission. (playstationlifestyle.net)
These produced a number of key mission documents that until the publication of this anthology have been available only in scattered form. (firstthings.com)
The world is literally filled with things to do within the story and several key missions that go about the true nature of the Cars brand which of course is racing. (gameluster.com)