Verity Jane, gifted app whisperer, takes a job as the beta tester for a new product: a digital assistant, accessed through a pair of ordinary-looking glasses. "Eunice," the disarmingly human AI in the glasses, manifests a face, a fragmentary past, and a canny grasp of combat strategy. Realizing that her cryptic new employers don't yet know how powerful and valuable Eunice is, Verity instinctively decides that it's best they don't. Meanwhile, a century ahead in London, in a different time line entirely, Wilf Netherton works amid plutocrats and plunderers, survivors of the slow and steady apocalypse known as the jackpot. His boss, the enigmatic Ainsley Lowbeer, can look into alternate pasts and nudge their ultimate directions. Verity and Eunice are her current project. Wilf can see what Verity and Eunice can't: their own version of the jackpot, just around the corner, and the roles they both may play in it.