Summertime brings the Fletcher Family back to Rock Island where the good times never end, but this summer the boys' favorite lighthouse is all boarded up and with the help from their new neighbors, the Garcia girls, the boys are determined to find out what is really happening with their lighthouse and saving it, no matter what the cost.

Although not thrilled when her summer plans are upended for a surprise cross-country train trip with her family and embarrassed because one of her moms is writing a tell-all book about the trip, twelve-year-old Sara Johnston-Fischer finds herself changing along with the landscape outside the train windows.