The Map of Bones by Francesca Haig

This is the second in the Fire Sermon series, a dystopian tale set a few hundred years after the nuclear destruction or devastation of earth.A DNA mutation caused by the radiation of the initial blast has caused a splintering of the population.

Each pregnancy is a set of twins, one of which is born with some kind of mutation, ergo the lesser of the two. They are called the Omega and the perfect twin is called the Alpha.

The twins are connected via a life-bond. If one dies the other automatically dies the same way. The Alphas reject their twins, and so does society. I'm sure if it wasn't for the pesky 'if I die you die' element of their sibling relationship, the majority of the Alphas would just kill their Omega sibling. Instead the Alphas have found a variety of nefarious methods to rid themselves of their 'broken' other halves without actually killing them. Might as well be though.

The Omegas have built a network of resistance across the country, and despite the really bad odds are still trying to outwit the Alphas. They are also trying to find out whether there is anyone else out there in the big world. Literally in the Elsewhere.

Cass is still reeling from the shocking revelations about Kip and his demise. As a seer she is both a pariah to her peers and a beacon of hope. They need her to have visions, but are frightened of them at the same time.

The Fire Sermon series is an eclectic mix of post-nuclear devastation, dystopian world-building and the usual YA tropes. Some of the topics sail pretty close to what could become a reality if we are ever faced with a nuclear disaster on a major scale. Underground bunkers, the aftermath of the destruction the inevitable changes or mutations caused by radiation.
A good read.

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