You Know What to Do

My entry shows Herry, Ron and Hermione IN Aberforth Dumbledores Pub.

After initially trying to dissuade the three outlaws from returning to Hogwarts, Aberforth tells the painting of his sister Ariana "You know what to do".

She walks into the background of her picture. Some time later she can be seen walking back. Followed by someone: Neville Longbottom!

The portrait swings open and Neville shows Harry, Ron and Hermione the way through the secret magical passage back to Hogwarts. 

I've always loved Hogwarts moving portraits. Ariana Dumbledore helping the Rebels through the magic of her portrait is my favorite Back to Hogwarts moment.