The Repository of the victorious dead…
Sometimes a painting is just a painting.
This is not one of those times.
The dread Tower of Inversion, lair of the vile lich Zarakoth Xorast, contains five layers, each containing different tools of dark magic.
Water drips from the ceiling in a steady rhythm. Water refracts torchlight, illuminating the depths of the pools with reflected torchlight.
The player characters, experienced and somewhat well known, hear rumors and travelers' tales about a distant area being overrun by dragons (or other terrifying monstrosities). The locals have sent them a message, begging for heroic aid.
When they investigate, they discover that nothing of the sort is going on. It turns out that a group of thieves wanted them out of the way so that they could rob them (or someone who would normally receive their protection).