From the back of the book:
DROW INVADE UNDERMOUNTAIN!
The players think their characters are invincible. It's time for you to show them otherwise. Gather your players— the tacticians, the rules experts, and the power gamers—and let them test their mettle against the drow in the depths of Undermountain!
Spiderkiller is a Dungeons and Dragons Roleplaying game challenge designed for the 2012 summer installment of the D&D Lair Assault official play program. It includes one full-color battlemap, one sheet of tokens, a laminated play aid, and information on the D&D Lair Assault program.