How would you feel if your little sister disappeared on your watch? Carmel Hamilton makes a selfish decision which results in the kidnapping of little Polly. The situation is further exacerbated when another member of the family sustains dreadful injuries. Shunned by her father and elder sister, Carmel sinks to the depths of guilt and misery fearing she will never again be deserving of love. Ellis Towers finds the key to unlock the Hamiltons' deeply buried secrets - but what he discovers could save or destroy the whole family. What Happened to Polly is a mystery drama following a moment in time when the decision of one changed the lives of many.