The Bookshop Below by Georgia Summers

Below the streets of London, a secret network of magical bookshops has existed for millennia. But they’re slowly disappearing, and no one knows why. Only one dishonored bookseller can uncover the truth and rewrite her story.

If you want a story that will change your life, Chiron’s bookshop is where you go. For those lucky enough to grace its doors, it’s a glimpse into a world of powerful bargains and deadly ink magic. For Cassandra Fairfax, it’s a reminder of everything she lost, when Chiron kicked her out and all but shuttered the shop. Since then, she’s used her skills in less ethical ways, trading stolen books and magical readings to wealthy playboys and unscrupulous collectors.

Then Chiron dies under mysterious circumstances. And if Cassandra knows anything, it’s this: the bookshop must always have an owner. But she's not the only one interested. There's Lowell Sharpe, a dark-eyed, regrettably handsome bookseller she can't seem to stop bumping into; rival owners who threaten Cassandra from the shadows; and, of course, Chiron's murderer, who is still on the loose. As Cassandra tries to uncover the secrets her mentor left behind, a sinister force threatens to unravel the world of the magical bookshops entirely ...