What Hestia did next, following Gideon's denial, was fast, too fast for Mory to stop it even when she raised her wand a second after Hestia captured her own again from the floor. The first was a ward to the main part of the house so no one from that area, such as the Aurors, would hear anything.
The next was aimed at Gideon, a powerful spell used by the Ministry to discover hidden Dark Marks by whatever magical means they could be concealed. And she didn't stop at one, but repeatedly battered at the illusion wrapped around the man before her. It had to be an illusion, as she couldn't wrap her mind around the idea he was inhabiting another body.
While Mory hadn't been able to stop the ward or the first two rapid-fire casts of Hestia's, she did cut off the third by disarming the woman with a vicious swish of her own wand, the sting Hestia would likely feel one that was unintentional. Mory was simply terrified of what would happen if the proof was given.
But it was too late. With the emotional force of Hestia's battering of the skilled web of illusions, the interrupted third cast still carried enough power to deliver the last shattering blow to the branching cracks in the disguise, leaving Gideon Prewett where 'Wyatt Alexander' had been a second ago.
Mory couldn't act further, however, as a wand pressed firmly to her back, a silent warning she did heed, heart dropping to her toes as it happened. She was fearless – insanely so – but this, this was all her terrors come to life.
Hestia, though – Hestia could act further and did when the man before her was none other than Gideon Prewett – aged and scarred but unmistakable. "Mistaken!" she all but screeched and then swung, her fist connecting with Gideon's face a moment later. "You wretched, sodding bastard!"
But even that wasn't enough for the hormone-aided well of emotion building to breaking point, and so, with a wild cry of anger mixed with pain, she began to pummel him.