illie Bassett is sad, and she doesn't understand why. Her parents and friends suggest very different, allegedly helpful, remedies. But it is the suggestion of her counsellor, Gilbert the Goldfish, that the answer may lie in finding the nature of happiness. As Tillie embarks upon her project she discovers that, when it comes to family and friends, nothing is quite as it seems. Secrets are uncovered, old tensions resurface, relationships tangle and untangle, and Tillie realises that everyone struggles balancing sadness and happiness, and living truthfully.