Herrick's Lie - T. M. Blanchet - Bog

Underground.
Underwater.
Out of time.
Ollie had only wanted to make things better at Herrick's End. And he thought he had, until he sees the stark truth spelled out in black-and-white: His friends are in danger, and it's all his fault.
The good news? There might be a solution. The less-good news? It's hidden at the bottom of a deep, dangerous lake. Leaping into that water, he knows, is a monstrously bad idea.
It's also the only idea he's got.
One thing is certain: Ollie's quest to right past wrongs is about to open up a whole new can of wormwalkers in the extraordinary underground world he now calls home.