Fearsome Destiny: Brothers and Sisters (The Fearsome Destiny Series Book 1) by Joseph Amiel

VICTORY CAN GAIN THEM THE THRONE! FEARSOME BROTHERS AND SISTERS is the thrilling saga of a boy, Gallin, and a girl, Alexine, lifelong friends, who escape an assassin on their shared 17th birthday only to face mortal danger on a different world, but also the prospect of greater power and purpose than they could have ever imagined. It is the first book in the Fearsome Destiny series. Dropped into a strange version of 1776 London, they join the crowd outside Westminster Abbey viewing the televised celebration of the combined 17th birthday and Elevation into adulthood of the king's son and his future bride. Shockingly, the two look exactly like Gallin and Alexine, who must go on the run to evade arrest for the capital crime of impersonating royalty--actually the identical twins from whom they were separated at birth. When captured, Gallin cleverly evades his and Alexine’s televised beheadings by claiming the ancient right of Trials by Combat, duels to the death to prove they are the elder twins and entitled to become the future king and queen. Alarmingly, they have only a month at the Royal Academy to learn the lethal combat skills their warrior siblings have trained in there for years. The increasingly deranged tyrant king has his own reasons for their elimination and, in that effort, reveals to a populace kept in medieval ignorance for centuries much of the ruling class's astonishing and intimidating secret technology, such as interplanetary travel, flying belts, and invisible aircraft. The battles shift from London's palace and alleys to a TV spectacle fought with swords in mid-air over Philadelphia, the city where their new friends--Benjamin Franklin, John Adams, and Thomas Jefferson--are debating independence from the Crown. As dark mysteries hidden in the past unravel and alliances shift, Gallin and Alexine are plunged into the perils of an American Revolution far different from what they studied in school.
If you loved The Hunger Games...