There is an unexplored land appearing at the end of the ice age. Players are the heads of five fantastical races setting out to cultivate this mysterious land. Though pioneering this land is a collaborative effort, the other races are mischievous and may be disturbing your progress while pretending to cooperate. Alluvium is a flip-and-write game with a twist: after each round, the sheets are passed clockwise to the next player and the sheets will come back to the original player with multicolored shapes from each of the opponents' work. Each turn, a card is flipped. Players then draw that shape in their color in an empty area on the sheet in front of them. By helping to make a larger contiguous area, they will earn cooperation points toward a bonus, but they will also be helping the owner of the sheet get a higher score. After drawing the shape, players pass their sheets to the player on their left and repeat.