Twins

The Saskias, Saskia Chandler and Saskia Hunt, lead double lives. Quite apart from being ordinary young girls holding down ordinary jobs, they are also the super-powerful SuperTwins, and the jobs they manage to hold down while being the twins are decidedly not ordinary. Impossible things for the Air Force and fixing problems with tangled timelines in the past are all in a days work for Kyra and Katya. This ability to travel in time, with a little help from Voice, their disembodied guide and mentor, comes in useful when they become involved with the security services and an assassination attempt. Throughout all this, they attempt to lead normal lives, although Saskia Chandler is decidedly not a normal girl. The girls eventually come to the conclusion that far from being Richie, as she began her life, she's always been Saskia, which appears a little odd, but makes perfect sense to them.