[Frontier]

Originally Posted by Kanon

The answer to that is on the official website (the Japanese one).

Spoiler for Just in case people don't want to know:

The mother specifically sent Suletta to that school as part of a ploy to take revenge on the people who killed her husband and colleagues. Suletta doesn't know, the mother only told Aerial who didn't want Suletta to get involved because she's a very sweet girl. Sadly, Mommy can't hear Aerial's voice, and her mind is set on revenge anyway.

Suletta becoming Miorine's fiance is part of the plan by the way.

Spoiler:

Wow, we're legit getting a sentient Gundam .

I've also seen some speculation that the masked woman might actually be Suletta's mom.