Bring water to boil in kettle, put rhubarb in and leave 3 to 5 minutes, then drain in colander. Set aside.
Blend sugar, flour, nutmeg, and butter, then add eggs. Beat till smooth and add rhubarb. Pour into unbaked pastry shell, top with pastry crust.
Bake in hot oven at 425 degrees for 10 minutes, then turn down to 350 for about 30 minutes.