This is the first minigame in year 4. This is very fun and easy. Just swim until you reach the Merpeople. They attack the ones coming at you by waving your wand towards them. You will see water jet from them once they start to come at you. Then dodge them once they all start charging at you. At the end you will need to attack the Merpeople and in your spare time cast the spell at the ropes of Ron and Gabrielle until the number reaches zero and then float up. Hurry though, you will run out of air if you don't do this quick enough.