You have to think of this as less of a sequel to The Giver, but as an alternate community popping up in the post-apocalyptic world. This could, possibly, be at the same time.
Kira is recently orphaned and lame from birth. The community only allows healthy children to live past birth, so she is an anomaly in this community. Most of the others are used to working hard, hunting, and fighting amongst each other. Kira must stand up to strong desire to get rid of her. She finds a protector in Jameson who recognizes her artistry with thread, weaving, and materials. As we get further into the book, we are under the suspicion that maybe these orphaned children who are helping keep the traditions alive in the community are not orphaned by accident or fate.
We also learn that there may be other communities out there.