Vanda Sudbury and Robert, the Earl of Cunningham, have been friends since childhood. They know all of each other's faults and weaknesses and squabble like brother and sister. So when her father tries to force a marriage between them, they are both horrified.

Fond though he is of Vanda, Robert is sure he could never love such a forceful, strong-minded woman. She is equally dismissive of him as a husband. Together they flee, going first to France to see the great Paris Exposition and to climb the newly built Eiffel Tower. That is only the first of their adventures, which also include traveling to Vienna on the Orient Express and on to the romantic city of Venice. Along the way they learn even more about each other, and for the first time in his life Robert experiences passionate jealousy, suddenly seeing Vanda in a whole new light. By the time they reach the temples of love in Greece, they no longer feel like siblings.

But when tragedy strikes, they must face their true feelings for each other.