Use the hearthstone to return to Stormwind. After returning to Stormwind, find the guards guarding the city in Stormwind.

When you find the guard, ask the location of the guard bank. The third step is to open the map, check the position marked by the guards and run to the bank according to the marked position. In the bank, you can find the guild warehouse of the bank, click the icon of the guild warehouse, and you can go in.

Story background (the shadow of Naxxramas)

C 'Thun, an ancient god, is hidden in the depths of Angela's temple. This monster, known as the Thousand-eyed Devil, lurks there like a nightmare. In order to curse the flesh and eat, he frantically lured his worm-draggers into Azeroth. Unfortunately, he finally fell into the hands of the alliance and tribal army under the leadership of Bronze Dragon. The world seems to have once again ushered in a brief peace.

Arthas, the former Prince of Lordaeron and now the Lich King, took too long to recover after fighting Illidan in the frozen throne. Now he is stronger than before. He will do better than Neruzu, the lich king, failed to do, so the natural disaster will come back again.

As a pioneer, Arthas' guide and loyal servant Kel 'Thuzad will lead the huge floating war fortress Naxxramas to this familiar and unfamiliar land of Azeroth.