Dungeons & Dragons: 1E Down The Shadowvein

You carefully load your canoes and launch into the fast-moving waters of the underground river named Shadowvein. The Pod-Caverns of the Sinister Shroom behind you, the veracity of the map that is to be your guide into the dark unknown will soon be tested. Hopefully what is written is accurate, but if it is not, your wits, wile, and brawn should serve you well as you journey down the Shadowvein!