From the publisher:
Casters have long used magic to settle their disputes, often with disastrous effects. Over the years, these duels developed into the codified contest of skill and cunning that we have today: the Duel of Wands. In Duel of Wands, players are attempting to prove themselves the superior caster, slinging spells at each other to try and remove their opponents Psyche and win the duel. Don't grow too confident in victory; between rounds, the loser will have the opportunity to study and improve their spells!