Valancy Stirling has been emotionally abused all her life, she is worn down into a shadow of a human, dependant on others (as many women were at the time), dealing with her wants and needs being neglected, she escapes in the works of John Foster, who writes about nature. She sometimes escapes to an imaginary place that is a blue castle.
Her life changes when she hears that she has a deadly heart condition and now she only has a short time to live and she decides that she's not going to live her life as it was, she's going to live her life as she wants. This leads her on an adventure that will change her life forever.
I really enjoyed it, found it uplifting and hopeful.