The Summoners Games: Book One In The Court of Mages Chronicles

In the lands of the Four Realms; Magique is the only way of life.
Every year, around the summer solstice, the strongest mages from every realm gather at the Court of Mages; the only place that is accessible to all four realms, for a giant competition, The Summoners Games, to discover who is the strongest mage.
Winner earns a position on the Magique Council.
Avalon Carlyle of the Third Realm knows this, and along with her best friend Ellia and the mysterious magic tomb called, Naedeverre, she ventures to tempt her powers and find adventure.
But Avalon soon finds out that all of the things that she has grown up believing in are not at all what they seem, and that things at the Court aren't always right., and maybe, just maybe, the Summoners Games are more deadly than Avalon had ever dreamed.