Halloween Heist!

Who- the players are a team of "adventurers" gathered together to rob a evil king. PCs will be 7th level, max 5 in any class, ideally should have least 1 level of Rogue and a good mix of combat, skill, and magic abilities. You can either have one +2 magic item, two +1 magic items or 4 uncommon magic items. (5 players maximum)
What- a heist of the swollen vaults of an evil king!
Where- Xinlenal the capital of the Netheril Empire!
When- a thousand years before the common era of 5th edition!
Why- Justice! Greed! Revenge! Adventure!