Nice story! Hooray for time-travel.

Two things... When you write, 'Rhian held her breath as other the next two hours she was cut, burned, bruised, and beaten. What finally broke her was when they cut her down and tied her to a table and threw salt water over her torn and bloody body.'--instead of just stating it that way, in a factual, dry way...don't state it at all.

Unless you're more then slightly sadistic, and really -want- to describe a full-blown torture scene (please don't)..let the reader come up with it. Just write that she held her breath...and then skip to her sobbing, etc, as salt water is being poured over her wounds, two hours later, and how she's such a wreck, and have the reader fill in the blanks with their own imagination--it'd be the power of suggestion at work. But writing that she was 'cut, burned, bruised, and beaten', in a very dry, unemotional way, removes the dramatics of it, and the awfulness/emotion/overall impact.

The other bit was that you might want to edit the part where the consequences of time-travel are being described in Chpt. 1--I just found that a bit confusing, and rather garbled. ("You better... otherwise you will go through the rest of eternity failing or otherwise dying each and every time. Please... succeed.")

Oh, one other thing. If they're sending their -most powerful- mage...wouldn't she know a bit more about the entire process of time-travel? Also, wouldn't she be able to get away from the Talia when she starts getting tortured...?

Anyhow, a few suggestions and thoughts. Happy writing!