An aging botanist withdraws to the seclusion of his family's vacation home in the German countryside. In his final days, he realizes that his life's work of scientific classification has led him astray from the hidden secrets of the natural world. As his body slows and his mind expands, he recalls his family's escape from budding fascism in Germany, his father's need to prune and control, and his tender moments with first loves. But as his disintegration into moss begins, his fascination with botany culminates in a profound understanding of life's meaning and his own mortality.

Visionary and poetic, Moss explores our fundamental human desires for both transcendence and connection and serves as a testament to our tenuous and intimate relationship with nature.