The old sea-dog, Captain Spike of the brigantine Molly Swash, calls out the order to first mate Mulford: the ship casts off with the tide -- and young Rose Budd is to be aboard!

For Rose and her kindly aunt, it is to be a voyage for rest, recuperation, and escape from a world beset with worries and the rampant "pulmonary" disease, tuberculosis. As they soon learn, however, the best-planned vacations can go in unexpected directions -- toward romance, perhaps . . . and more alarmingly toward danger.