Almost 90 pupils, teachers and parents, packed out the school’s gym on Friday night.
The theme was "Enchanted Forest".
For a brief period, a wireless speaker had to be plugged in and battery-powered lights were turned on before the power came back on.
Aside from the short blackout, it was a great night for everyone involved, East Otago High School assistant principal Helen McIntyre said.
It was a hit with the pupils as many cited that as their highlight from the evening.
Dr McIntyre said the school was grateful for all the local support it was given in preparation for the event.