The Ballad of the Bear & the Serpent

"Deep in the forbidding Akahnpek Jungle stands the Lost City of Salasmul. Though it fell centuries ago, its yuan-ti creators still linger; and they have a plan to return to glory. Orcs make brazen raids on civilized areas. A cult grows in strength in the jungle and away from prying eyes. In a few weeks there will be a lunar eclipse. Under that darkness, one of these factions will give rise to a new god. Your band of heroes has until then to shape the destiny of a nation. This adventure book provides material for three to six sessions of gameplay, and will see a party of 5th-level adventures progress to 7th-level. Welcome to the jungle!" Source: back of the book