Signs of Damage by Diana Reid

It was as if the present and the past were linked: a spider’s web, wherein a shock to one strand could make the whole structure shake.
The Kelly family's idyllic holiday in the South of France is disturbed when Cass, a thirteen-year-old girl, goes missing. She's discovered several hours later with no visible signs of injury. Everyone present dismisses the incident as a close brush with tragedy.

Sixteen years later, at a funeral for a member of the Kelly family, Cass collapses. The present and the past start to collide as buried secrets come to light and old doubts resurface. What really happened to Cass in the South of France? And what's wrong with her now?