Neville Longbottom has spent the majority of his life trying to live up to the legacy set by his parents. To do what they would have done, to make them proud. So when he discovers what is about to happen to one of his former classmates, agreeing to help her is an easy promise to make.
Even if it means marrying Pansy Parkinson.
As her secrets unfold, however, and he begins to see beyond her manipulations to the person she truly is, he begins to question how he will ever be able to keep his promise to free her in the end.