Trained from early childhood in self-defense by her Military-based family, Jamie has grown into an expert combatant with a prodigious talent for solving mysteries - so prodigious, in fact, that her parents attempt to curb her exuberance by packing her off to an exclusive finishing school in Switzerland. Unwilling to tolerate the restrictions of traditional College life, Jamie promptly runs away, eventually returning to London two years prior to the outbreak of WW2. Now aged 18, she manages to find work with a local theatre company, starting out as a low-paid chorus girl. Gradually working her way up the ranks to become a top performer, Jamie becomes an expert acrobat, dancer and tumbler.
Some time later, when a gang of West End thugs attempt to extort money from her employers, Jamie quickly takes them down with a dazzling display of Combat Gymnastics, making headlines as the High-Kicking Queen of Shaftesbury Lane. Her reputation grows as she starts spending her free time investigating local crime as an amateur sleuth. Aided by her best friend Patrica Hawkridge and circus strongman Victor Neveroyatnyy (Russian for "the unbelievable"), Jamie begins cleaning up the back streets of London's theatre districts.
Her unusual abilities bring Jamie to the attention of the British Intelligence Bureau, which offers her a position as an undercover agent. Eager to serve her country, Jamie agrees without hesitation. Her assignment is to travel the country with a military revue company, ferreting out Nazi spies and saboteurs.