(Until she has a name I'll refer to her as 533)

A black armored truck rolls up to the academy and stops outside the central square. On the sides the SHIELD insignia was clearly visible. It wasn't too often that they would be seen interacting with the heroes and villains of the academy. Better to not be associated as much as possible. But today they had a special delivery. Awaiting their arrival was Superman and Martian Manhunter. The ramp on the back folded down and a girl was escorted out. Her arms were locked together by braces that encased her hands an forearms. Brought before the heroes the martian spoke. "There's no need for restraints here. Release her." 

No sooner were her hands free did she turn on the shield agent who took off the braces. Grabbing the restraint she whipped it around and slammed it into the side of the mans head. The other agents quickly took aim but that didn't stop her. Before they could get a shot off through Superman intervened and lifted her off the ground. She landed a couple punches and kicks the man of steel's face but it didn't phase him. Realizing the futility she quit struggling and glared at everyone. "That's enough. Now calm down, we're not here to hurt you." Superman said as he set her back on the ground. Swatting his hand away the girl scoffed. "Everybody says that. No one ever means it." 

Crossing her arms 533 looked at the academy. What was this? Some sort of trick so she would lower her guard. As if. Sure it looked nicer than anywhere she'd ever been but it couldn't be for real. Even if it was the people here couldn't be trusted, especially if SHIELD felt they could leave her in their care. Glancing at the heroes again it didn't look like she could take them. Behind her the agents wouldn't be that difficult. But then there was still getting away which was easier said than done. As a precaution a tracker bracelet had been locked around her ankle. For the moment it looked like she was just going to have to bide her time until she could shake the tracer. Glaring at them all again 533 rolled her eyes. "Alright, let's go." 

Lead inside and brought up to speed about the academy's purpose she was given everything to get started the next day. What happened next was a big surprise. They let her loose to explore the grounds. No obvious escort or someone watching over her shoulder. Though they didn't need to be present to keep tabs on her, but it was still unusual given the constant surveillance she was used to both in the lab and SHIELD. After standing at the front for several minutes she decided to take a look around. The least she could do is learn the layout so she could get around and possibly escape. The cafeteria sounded like a good place to start. Hopefully that had better rations than to go with everything else.