Cass opened her eyes. Lifting her head to peer through a portal, still strapped to the bed at the waist, she could just make out the Quietener: a blue glint reflecting off the hull a million kilometres away. Mimosa Station had so little room to spare that she'd had to settle for a body two millimetres high, which rendered her vision less acute than usual. The combination of weightlessness, vacuum, and insectile dimensions did make her feel pleasantly robust, though: her mass had shrunk a thousand times more than the cross-sections of her muscles and tendons, so the pressures and strains involved in any collision were feather-light. Even if she charged straight into a ceramic wall, it felt like being stopped by a barricade of petals.
It was a pity the same magical resilience couldn't apply to her encounters with less tangible obstacles. She'd left Earth with no guarantee that the Mimosans would see any merit in her proposal, but it was only in the last few days that she'd begun to face up to the possibility of a bruising rejection. She could have presented her entire case from home, stoically accepting a seven-hundred-and-forty-year delay between each stage of the argument. Or she could have sent a Surrogate, well-briefed but non-sentient, to plead on her behalf. But she'd succumbed to a mixture of impatience and a sense of proprietorship, and transmitted herself blind.
Now the verdict was less than two hours away.
For twenty thousand years, every observable phenomenon in the universe has been successfully explained by the Sarumpaet Rules: the laws governing the dynamics of the quantum graphs that underlie all the constituents of matter and the geometric structure of spacetime. Now Cass has stumbled on a set of quantum graphs that might comprise the fundamental particles of an entirely different kind of physics, and she has travelled three hundred and seventy light years to Mimosa Station, a remote experimental facility, in the hope of bringing this tantalising alternative to life. The “novo-vacuum” is predicted to begin decaying the instant it's created, but even a short-lived, microscopic speck could shed light on the origins of the universe, and test the Sarumpaet Rules more rigorously than ever before.
Cass's experiment turns out to be more successful than anticipated: the novo-vacuum is more stable than the ordinary vacuum around it, and a region in which the new physics holds sway proceeds to expand out from Mimosa at half the speed of light.
Six hundred years later, more than two thousand inhabited systems have been lost to the novo-vacuum. On the Rindler, a ship that has matched velocities with the encroaching border, people have come from throughout inhabited space to study the phenomenon. Most are Preservationists, hunting for a way to turn back the tide, but a few belong to another faction: Yielders, who believe that the challenge of adapting to survive on the far side of the border would reinvigorate a civilisation that has grown stale and insular.
Tchicaya has come to the Rindler to join the Yielders, but when Mariama — a childhood friend whose example inspired him to abandon his own home world and traditions for a life of travel — arrives soon after, he is shocked to discover that she plans to help the Preservationists find a way to destroy the novo-vacuum.
As a theoretical breakthrough leads to a sequence of experiments that begins to reveal the true richness of the world behind the border, tensions between the opposing factions grow. When a splinter group responds to these revelations with violent, unilateral action, Tchicaya and Mariama are forced into an uneasy alliance, and travel together through the border, balancing old and new loyalties against the fate of two incomparably different universes.
I do not approve of the practice of using quotes from authors on book jackets, since I believe it blurs the distinction between advertising copy writing and reviewing. I've never provided such quotes myself, or sought them for my own books. However, because I neglected to tell my new editor at Gollancz how I felt about this, the UK editions of Schild's Ladder have some comments by Stephen Baxter on the jacket, alongside the excerpts from bona fide reviews of previous books. This glitch was my fault entirely, of course, and I'll do my best to ensure that nothing similar happens again.