If you haven't read War Girls: In 2172, much of the Earth is unlivable, and those rich enough and lucky enough to escape have abandoned the planet for colonies in the sky. Sisters Onyii and Ify live in war-torn Nigeria, where soldiers are outfitted with bionic limbs and artificial organs so they might be protected from the radiation-heavy climate.
What it's about: Five years after the Biafran War, Ify is a high-ranking medical officer in the Space Colonies, helping refugees rebuild their lives. Back in Nigeria, Uzo is a young synth, working to preserve memories of those lost. When a virus breaks out in the Space Colonies among children, their paths collide. Onyebuchi is a must-read author, and this duology is proof of that.
For other excellent sequels, read Spell Starter by Elsie Chapman, The Faithless Hawk by Margaret Owen, Iron Heart by Nina Varela and The Ever Cruel Kingdom by Rin Chupeco
Get it from Bookshop, Target, or from your local bookstore through Indiebound here.