The priest of Orcus is chanting over a book, written in blood and bound in human flesh.

Skeletons and flesh golems stand between you and him, and the ground is slick with blood from dozens of human sacrifices you had to pass by on the level above. Long chains as thick as your waist hang down from the ceiling, channeling the blood.

The portal, a yawning hole in reality, black as pitch and circled with runes, swells from within as if something is pushing on it from the other side.

You have sixty seconds before the portal is opened and the armies of the Shadowfell pour through, invading your world and covering it in darkness.

[While I'm sure it's tempting, please refrain from helping the priest of Orcus. He'll succeed just fine without your help, thanks, and you aren't going to like it when he does.]