"So."  Severus said.  "Now we’re all here.  Some time ago, Hermione cast an Obliviate charm upon her mother and father before setting off hunting horcruxes with Mr. Weasley and Mr. Potter.  Now that things have settled and the unpleasant business with Mr. Weasley is out of the way, she feels the time may be appropriate to go to locate her parents in Australia and restore their memories."