Kill a multitome lurker, a mutlitome evoker, and a mutlitome howler to dismiss the magical barrier. Once inside inspect the second row from the bottom on the middle book case. A bit toward the right you will see book title come up about Locks. Right click and read the entry for this quest. NOTE: You may need to be on or have done star to unlock to get this update. I was with a group on this part a few days ago and none of them could seem to get it.
Note: I was unable to get the update from the book until I had the "A Star to Unlock" quest. Then it let me update both quests. In order to get the "A Star to Unlock" quest you have to get to that quest in the "Legend of the Claymore" storyline. Gemtwist 04:07, December 3, 2010 (UTC)Saytawe
Once you have these, you need to go craft a key. This is done by simply going over to the table and clicking through the prompts that appear. This gives you a working key
Head back to the chest and use your key. Your reward is a 5 charge Chiller Bomb. This item does random cold AoE damage(depends on INT) and has a 46% slow.