The Book of Betrayal — Melissa McShane

Helena Davies knows all about keeping secrets.

Now her secrets will come to light.

Helena's encounter with a terrible creature whose kind are
bent on destroying the world revealed a terrible truth: a cabal of rogue humans
works with those monsters, intent on gaining power. Charged to remain silent
while her superiors prepare to attack the traitors, Helena fears trusting her
friends, her colleagues, even her secret lover Malcolm Campbell. Any of them
might betray her.

When an unexpected attack by the hidden enemy devastates
magi around the world, it draws Helena deeper into the web of conspiracy. With
Malcolm suffering his own loss, and friends betraying friends, Helena confronts
the reality that no secret can last forever.