Hungry Like the Wolf

Remus's daughter, Celia, is eleven years old, and she refuses to take her Wolfsbane potion. Can her Uncle Severus convince her that it's necessary? (Set in "Parents With a Cause" universe, which is a crossover universe between NCIS, House, MD, and Harry Potter. This one is almost exclusively Harry Potter, though, with a slight NCIS mention. Can be read as a stand-alone piece.)