Assassinate me

Fionnlagh and his younger sister, Sorcha, have been under the watchful eyes of King Aldus, a power hungry tyrant, since they were kidnapped 10 years ago. Fionnlagh, now 18, has grown to look very much like Princess Rohesia, the daughter and only heir of King Aldus. In order to keep his daughter safe from blood thirsty assassins King Aldus tells Fionnlagh to be Princess Rohesia for an upcoming ball or else Sorcha will be killed. What happens when things don't go according to plan and Fionnlagh is instead kidnapped by the assassins?

This is out because my friend Billie said I should do it.