This book starts in the present time where Lacey's mother is dying and it's time to turn the life support off and we watch as she says her goodbyes. The novel then flips twenty years in the past when Lacey is eighteen years old. Her mother has always said since Lacey was younger that she was possessed by Demons and Lacey believed her. Lacey couldn't do anything right and felt controlled by her mother and she had only two close friends Emma and Jo that she could rely on to keep her sane. During a party at her friend Jo's house, she meet Walker. The pair despite Lacey's objections start dating and things are going amazing and then her mother finds out and hits her so hard she blackouts. Right through this book we watch the dynamics between Lacey and her family and how her mother's partner and sister always take her mother's side and support the demon possession idea which makes Lacey believe it even more. Lacey then meets Walker's family and things are great and she talks with Walker's Aunty Linda about Mental Health which is what her mother has. The thing though that annoyed me with this book was that despite the way Lacey was treated, she still hung around her mother. I know on a personal level, what it is like to live with family members who have mental health and the control that they have over you and you do often feel too guilty to leave as all the "what if's" come floating in. What happens next is heartbreaking and I wanted to scream and shout at Walker as Lacey was supposed to meet him, but she was poisoned and locked away. Next thing we know Walker is back with Brittany - his evil-ex and engaged and eventually married her. I was wishing that he had a horrible life with her when I read this as I was all for #Team Lacey and wanted to shake him and go How could you be so stupid, you must have known there was a reason she couldn't come ? Really ?. To me , this book with it's flashback was about love lost due to mental health and the damage that living with somebody with Mental Health issues can cause us and that we are not alone and that it is important to get help as otherwise our lives will be controlled by their actions and we will find ourselves not able to be free from the pain . From reading the present as it doesn't talk much about Lacey's life now - I assume due to this past, she is a 38yr old single woman. For me this book felt unfinished and am hoping that maybe Lacey will finally get a HEA now she is free and who knows a possible second chance with Walker or someone better ? The Truth She Knew is definitely a thought-provoking story about what it is like to live with manipulative people and those with mental health issues.