Arthur, a cynical Boston book restorer, receives a 1920s journal containing a coded butterfly that pulls him into a biological mystery in Vermont. He discovers that a botanist and a mechanic once found a way to store human memories within the migration patterns and physical bodies of Monarch butterflies using a specialized "ink" made from ancient milkweed sap.
As developers move to destroy the ancestral grove, Arthur undergoes a "transmutation," becoming a living vessel for a century of recorded history to save the data from erasure. He survives a frozen winter as a biological monument, eventually releasing the stored memories back into the world through a new generation of wings, ensuring that the past survives even if the land is lost.
