Faced with a task that could turn them into monsters, Sarnd and Jessa must decide whether to run away or save the world.
Six years ago, twins Sarnd and Jessa thought they'd rid their world of the malevolent Serpentstone. Since then they've worked hard to set their shocking past behind them.
But the Serpentstone has returned, and they're asked to carry it to an abandoned mine where it will be sealed deep underground. The Stone appears to be much weaker than it was, but they learned the hard way never to trust it.
The Stone starts to regain its terrifying power, and while Sarnd is desperate to complete their mission so he can go back to his new life, Jessa has other ideas.
As the mission becomes a race against time, can the twins learn to trust each other and avoid becoming the creatures they fear the most?