From Starling:
Dive in, the water’s fine! Return to the magical world of Everdell with Pearlbrook, the first expansion for the critically-acclaimed game of worker placement, tableau building, and adorable critters!
Players will explore a new underwater society below Everdell’s Pearlbrook River. Pearlbrook introduces a new side board, the River board, where you’ll send your Frog Ambassador to gather a new resource, Pearls! You’ll also encounter new aquatic critters and constructions. 
During setup, the River board will be placed beside the main board. The new resource, pearls, will be placed in the Shoal. Four River Destination cards will be chosen at random and placed facedown and unseen on the four locations on the river. The basic Events from the base game are replaced with the four Wonders of Everdell. Finally, each player will receive a frog Ambassador and two Adornment cards (drawn randomly).
River Destination cards consist of Citizens and Locations. Players will send their frog Ambassador meeple to a destination to flip over the card and discover what awaits them below. The first player to visit an unrevealed River Destination automatically gains one pearl, as it is a race to see who can establish diplomatic connections with the waterfolk first!
