Wash the prunes, boil them and divide them into halves. The pumpkin is peeled and cut into cubes.
Boil the sugar and water to make syrup and add the pumpkins and plums to it. Boil on high heat. When everything is tender, stir well, add vinegar and boil for a dozen minutes.
Place the jam in dry jars, tie them with parchment paper and put caps on. Store in a cool, dark place.