After her brother is nearly killed while bringing sensitive information to his superiors, Margaret "Maggie" Ingleton takes it upon herself to complete his mission. All she has to do is deliver a letter to London. How hard can it be? Little does she realize that she'll be risking not only her life, but that of the only man she's ever loved.

When Colin Stanbury makes a routine delivery to his home city he never expects to pick up a stowaway. Maggie has always been a heady mix of proper lady and imp so finding her aboard his airship can only mean trouble. Despite Maggie's claim that she needs to go to London to help a friend in need, he suspects she's up to something. Yet he can't help playing the gallant hero to her damsel in distress.