Their performance was called Uncovering Alice and it was all about Lake Alice Hospital, a former rural psychiatric facility in Rangitikei.
WHS dance teacher Olivia Reuters said that when researching the facility, they came across a story about a young Niuean boy.
"He was put into Lake Alice because of his behavioural issues, when really, he just couldn't speak English," Reuters said.
"They could write letters home, but they were censored by the staff and if they said anything about what was happening there, they had to re-write it.
"He wrote a letter saying that he was having a jolly time, he drew a picture with it and in a speech bubble he wrote in Niuean that he was getting electroshock therapy which was painful."
The boy was Hakeaga Halo, his grandmother received the letter in Auckland and Lake Alice hospital was exposed.
The government wrote a letter of apology in 2001 for the abuse that occurred there in the 1970s and it has paid out more than $10m in compensation to almost 200 former patients.
A former Whanganui High School student, Reuters said the event was the highlight of her first year teaching there.
"Stage Art was time-consuming, but if it's something you love, then you've got no problem pouring your time into it and giving it your all," she said.
"When you're doing a topic like that, you're naturally interested in the performance, which gives you an energy and enthusiasm that seems to be contagious."
Stage Art is in its first year and was started by Dean McKerras of DanceNZ Made following the announcement that Stage Challenge would not run in 2018.
There were almost 100 students involved in the production and all of the arts departments contributed something, from music to visual effects.
All of the Stage Art performances were filmed and will be shown to a panel of judges to determine the winner of the national final.
"You don't actually get to perform it again, which is a real shame because it would be great if we could," Reuters said.
"It brings joy to everyone, performing uses a different part of the brain and it definitely builds confidence, I've seen that."
The performance opened with a girl reading a letter, before being taken away by nurses and shocked by a doctor.
Reuters said that despite the heavy theme, they still managed to incorporate an upbeat scene depicting patients with their families before being taken to the hospital.
When the judges announced Whanganui High School as the winners, Reuters said it was music to her ears.
"I felt on top of the world, when you throw everything into four weeks, you're thinking about it when you fall asleep and again when you wake up.
"To get such a reward was amazing."