What is the basic storyline of wow the burning crusade

On Azeroth, tidings are grim as the Blood Elves and Draenei arrive, spreading hints of bad things happening on the old world of Draenor - now known as Outland. As the dark portal opens, the people of Azeroth begin excursions into this forgotten world, torn apart when Gul'dan last opened the dark portal.

The heroes discover that Lady Vashj is attempting to drain the marshes, while Kael'thas desires to cause chaos through his Blood Elf armies attempting to gain more and more power. And all the while, the banished demonhunter Illidan sits in the Black Temple, plotting to regain all he has lost.

After the defeat of Vashj, Kael'thas and Illidan, it turns out an even greater threat looms. Resurrected by his new master, Kil'jaeden, we find Kael'thas returning from the dead to capture the Sunwell and bring his infernal master into Azeroth. Only the heroes can stop the demonic guardians in the Sunwell and push Kil'jaeden back.