Cindy Van Schacht is lost in the Mall of Lost Souls. Considering that Cindy isn’t quite all there, this is an even bigger problem than it would be for a normal person. But not to worry! Jane Harris, resourceful and intrepid fourteen-year-old friend, and Miranda Milan, legendary witch, are determined to rescue Cindy. However, they are still in the Mall of Lost Souls, and the mall knows how to confuse them with “Questions of identity” in chapter 14 of Summer of the Netherfield Witch. Good luck, Cindy! (You’ll need it.)
A historical question of identity: the Man in the Iron Mask (died 1703), as depicted in 1789
Sillyverse 
I like the theory (unlikely though it is) offered by the 1997 film by that name—starring, amongst many, Leonardo DiCaprio and Jeremy Irons (perhaps at his best in this, positively sparkling with subtle humour—said humour is more blatant when he plays naff parts in naff movies). Theory being that Louis XIV (King of France) had a twin, and the Man in the Mask was, initially, said twin, later said king. Oops, good move, if you’re not seen it I’ve now spoiled it. Shucks.