V.E Schwab 
Shades of Magic 
The Steel Prince #7

Through Isra’s guidance, Prince Maxim Maresh has entered the Night of Knives, a mysterious magical tournament, to prove his mettle and win the respect of his soldiers. Under the gaze of the Verose garrison and its population, Maxim had successfully survived the first challenge – a blizzard of magical shards when, while walking along a tightrope of magic steel rope, he was struck by a deadly bolt and sent plunging into the abyss…