Drowning in shadows and secrets

Rieta was on her way back to Bryseis' room at Blackstaff Academy, where she had been staying ever since being kidnapped from her room at the Gray Gryphon Inn, from a late night out. "I think I'll be able to convert that cute but dim-witted boy to worship of Asmodeus yet. I just have to work a bit harder," she thought to herself. The door to Bryseis' room was slightly ajar. Rieta pushed the door open as quietly as she could and peeked her head in. Bryseis was nowhere to be found.
 
"Must be a wild night in the library for her," Rieta joked quietly. "At least I won't have to listen to one of her lectures." She slipped inside and almost made it to Bryseis' desk before...
 
"Must have been a late night out in the pubs for you, wasn't it?" snapped Bryseis as she stepped out from the shadows behind the door. Rieta spun on her heels to face her in shock. The door slammed shut.
 
"Or perhaps you were on a long walk in the gardens to converse with our ancestor," Bryseis continued sharply. "Or perhaps...you were elsewhere? I saw my friend Lyra recently. She told me to give you this..." Bryseis held up a letter with Rieta's name on it. "... and that she suspected that you had gotten yourself involved in something nefarious. Just what have you gotten yourself into?"
 
Rieta filled to the brim with rage and tried to hurl an eldritch blast at her sister. It fizzled immediately. She tried again and the ruby glow immediately dimmed from her hands.
 
"You should know by now that our ancestor has no power here," Bryseis said with a smirk, just before being beaned in the forehead with a book. "OW! A book? Really?" Rieta threw two more books at Bryseis. Both missed their target.
 
"You sure have a lot of books on your shelves," Rieta taunted. "Some in fact are quite heavy, and you know full well that I can throw things better than you can dodge them." Bryseis sighed heavily.
 
"I don't want to fight you Rieta! If you want continue throwing things at me, if you REALLY want to hurt me, then go ahead. I just want to know what's going on. I may not be the most observant person, but I HAVE noticed that you haven't quite been the same since you were kidnapped. What happened to you?" She took a few steps closer. Rieta grabbed a heavy tome and readied herself to attack. "Are you in trouble?" Bryseis took a few steps closer. Rieta glared at her. "Are you being held hostage? Is someone forcing you to do things against your will?" Bryseis moved closer. She could see the tears forming in Rieta's eyes. "It's okay." She stood before Rieta. "You're my sister. You can tell me."
 
"NO! I CAN'T!!!" Rieta cried, and broke down crying, collapsing into Bryseis' arms.
 
"There there," Bryseis consoled. "It's alright."
 
"No, it's really not," Rieta sobbed. "And it's not just you. It's everyone. I'm somehow beholden to Vanrack, and the Mistress of Secrets is involved, and I could die from even telling you that much, and..." she sniffled, "...Bry, I'm really in over my head here." Bryseis sighed and rolled her eyes.
 
"I have just about had my fill of evil gods," she grumbled, and hugged her sister tight. "Do you want my advice? Do you really, honestly want my advice?"
 
"Yes," Rieta replied.
 
"Go home, Rieta," said Bryseis, with a sigh. "Go home to Mom. If anyone can help you with this, she can."
 
"But..." Rieta began to protest.
 
"You've carried out your mission here," Bryseis continued. "You've informed me that Damakos is alive. I'm grateful that he is, but I have no idea yet what that could mean. Anyway, you've done what you needed to do, and you could stand to get away from whatever is influencing you here." Rieta nodded. "In the meantime, I suggest we both pray to Oghma that you'll be able to obtain the knowledge that you need to overcome this."