Combine the milk, water, oats, and salt in a medium saucepan over high heat. Bring the mixture to a boil, then reduce the heat to low and simmer for about 30 minutes, stirring occasionally, until the mixture thickens and the oats have absorbed the liquid. Stir in the brown sugar, orange zest, cinnamon, and nutmeg.
Combine the plums, water, and sugar in a medium skillet over medium-high heat. Bring to a boil, then reduce the heat to low and simmer for 5 to 6 minutes, until the fruit is softened and the liquid has thickened slightly. Stir in the blueberries and vanilla extract.
Spoon the oatmeal into bowls and top with the stewed fruit and some of their juices. Sprinkle the almonds over the top and serve.