The first book in the Flowers of Eden series introduced readers to Bryony Linwood, an orphan trying desperately to provide for her sisters in the shadow of the Great Depression. In Castles in the Clouds, we meet one of those sisters—Larkspur Linwood, a young woman who has a passion for teaching but yearns for something more than life as a small-town Arkansas schoolmarm.

Young and impressionable, Lark mistakes a college professor's interest for romantic love. When he offers her the chance to join his efforts to start a school in Kenya, she pictures herself bringing the light of knowledge to hundreds of African children eager to learn. But the menial tasks she's assigned at the school aren't so different from life on the farm where she grew up. Worse, her fragile heart is broken when she realizes her feelings for the charismatic professor are not returned. Miserable and deflated, she gives up and returns home.

Enter Professor Anson Schafer, whom she met briefly in Kenya. Partially blinded from an eye infection he contracted there, Professor Schafer cannot return to Africa. He has come to Lark's school to recruit teachers like her for a more modest venture—the founding of schools and relief efforts here in the U.S. for those struggling through the Depression.

Still stinging from her experience in Kenya, Lark is reluctant to risk leaving her familiar surroundings, but she knows how great the need has become, and—although this isn't the exciting life she'd envisioned—she finally agrees. As they work side by side, Lark begins to realize that the deepest satisfaction comes not so much from what you do, or where you do it, but from the attitude of your heart. She also slowly realizes that the gentle, determined Anson is the true love of her life.