Sort the blueberries and rinse briefly under cold water. Set aside 3 particularly large blueberries.
Wash the plum, pat dry, cut in half and core. Cut the pulp into small pieces.
Puree the berries, plums with the honey and a little soy milk. Add the rest of the soy milk and mix the drink well. Season the drink with lemon juice and pour it into a glass.
Wash the mint and pat dry. Put the remaining blueberries on a skewer and place it over the edge of the glass. Put the tip of a sprig of mint in between.