An American Architect joins a group tour to Spain and France. Leaving from Chicago, he purposely sits next to an attractive girl on the plane. But she is unwittingly slipped a special package to clear through customs. As they tour from country to country, different people attempt to secure the package that she does not know that she possesses until later. As the Architect attempts to help her, he also becomes closely involved with the girl and the package. They try to get rid of the package, but it is a dangerous business that becomes more serious as they reach Paris. The affair climaxes in an attempted escape to England.