From publisher blurb:
This adventure supplement is a special collaboration with another creator we feel fortunate to call a friend, Fernando Salvaterra. In the Tree of Lost Dreams, a group of level-7 adventurers comes to a place that sages and historians have studied for millennia. The realm of dreams and its secrets have eluded their research, though. There are so many things that mortals do not understand yet. The Tree of Lost Dreams, however, has all the answers. A Court of Oneiromancers also called ancient sages, or oracles, live an eternal sleep in the tree. This allows the tree to project any reality of any past dreams to its visitors..
The Tree of Lost Dreams does not grant any visitor what they want. A wise sphynx is in charge of testing visitors' will and wits. This sacred, ancient tree, may also be a gate. The door that takes the heroes to where they should be, or where they are needed the most. On the other side, messing with the oneiromancers and breaking the balance between the Material Plane and the realm of Dreams has dire consequences.
This is a level 7 encounter adventure that takes the heroes to a fantasy location called the Tree of Lost Dreams. There, they shall find the answers they need to continue their quest or find the truth about their current mission.