From the front page of the PDF:
Giants are raiding the civilized lands in large bands, visiting death and destruction upon villages, towns, and farmlands. Entire militias have been conquered, whole crops wiped out. Determined to repel the invaders, local lords have called for you to banish the marauding giants from the civilized lands. A Living Forgotten Realms adapted adventure set near the Evermoors for Adventure Level 12 (character levels 11-15).
This adventure is found in Issue 197 of Dungeon online, part of D&D Insider. Dungeon issues may be found on the Wizards of the Coast website (http://wizards.com/dnd). At least one person at the table (either a player or the DM) must have an active subscription to D&D Insider. This is the first part of the Against the Giants Major Quest. The other parts are ADAP4-4 Warrens of the Stone Giant Thane, ADAP4-5 Glacial Rift of the Frost Giant Jarl, and ADAP4-6 Halls of the Fire Giant King. You should play the parts in order. This is a very long adventure. We recommend that you allow at least fourteen hours of playing time.
This adaptation document does not present adjusted stat blocks for low/high tier; any LFR-legal AL 12 table can play, but bear in mind that the stat blocks in the adventure were written for a party of level 12-14 characters. Tables consisting entirely of brand- new 11th-level characters might find this adventure difficult; a table of all 15th-level characters might find it easy. The DM is encouraged to make adjustments as needed to ensure a fun time for the players and a challenging but fair experience for the PCs.