The Guardians and their doors.

Chapter Ive been planing this for weeks

McGonagall wasn't sure about anything other than the fact that the fae had far different ideas of acceptable behavior.

The first hint she received was when their third in command, Clarrisse, and a member of the support squad, Katie, got into a fight over a tree.

It was the whomping willow to be precise, and the blasted thing loved them both for as varying reasons as Katie and Clarrisse did.

Sprout was rather fond of Katie, seeing as her mere presence was enough to make the more vicious plants behave.

The second hint she received was finding the youngest looking, Jazz, she believed, cackling over a cauldron and quoting Hamlet while Alena, her best friend, and partner in crime cheered her on.

The potion apparently was useless unless you liked dramatic lights, excessive smoke, and explosions at random moments that covered everything within five feet with glitter.

At least she knew her stuff.

The third and final reason was when she looked out her office window to see them dragging a catapult across the grounds to use as a diving board. 

Steve, Percy, and Annabeth were giving points for style, accuracy, and technique.

They didn't really have a chance to talk much not having interacted with any of them. She hadn't even heard them sing, something Pomona and Sprout assured her "was the sweetest melody to be played on these grounds in years."

However, on the night of August 18, just as the sun went down, that changed.

McGonagall had found herself drawn to her office window overlooking the lake by the most sorrowful music she had ever heard in her life. Just listening made her remember those she had lost, both from battle and old age.

"If you must mourn, my love, mourn with the moon and the stars up above. If you must mourn, don't do it alone." The fae sang.

She didn't know how long she listened, only that every note made her heart pang with grief and tears flow from her eyes.

So when Dumbledore told her that the fae were going to put on a show she feared for the worse, having experienced how powerful their music could be first hand.

The drums started, soft chanting in Gaelic filling the great hall as the students quieted down.

Four fae girls in green and gold dresses dropped down from the rafters, hitting the floor and instantly bursting into song.

A violin appeared in one of the girl's hands and the melody began, upbeat and lively.

When they got to the chorus more voices joined in, hidden by the rafters.

After the chorus, they all raised a glass and the rest of the troupe dropped down, spinning in mesmerizing swirls that had to have some illusionary magic added in.

The extra dancers pulled back to the teacher's table, taking a drink of the transfigured wine and slamming the goblets down in time and two broke away from the backup dancers.

One was a girl in a silver parka, the other a boy with a red jacket on.

They raced down the Gryffindor and Slytherin tables respectively as the drums began their solo.

They both clapped their hands together and drew them apart slowly, lightning crackling between the girls and fire flaring between the boys.

The electricity and flames expanded, into shapes, shapes that the pair proceeded to juggle, spin, and skip rope with before throwing their powers towards each other.