There nothing left. Great answer.

 

Seems to point toward the slave...
@oldmarine ?
@DropDead ?
@02 LW300 ?

 

I do not have a VUE, that being said is the line steel with a rubber flex piece or plastic? My L200/5 has a steel line and what appears to be a brake hose to the slave. Unlike the Fords that I have worked on, my Saturn has the bleeder between the master and the slave down by the slave. This is a pain to bleed properly. The Fords have a line into the bell housing and a line out the top of the slave with a bleeder on it. That is a much better design in my opinion.
If you are satisfied with your master cylinder, replace the slave. There are only two parts.

 

I don't know how similar a Vue is to an Ion. When I bought my Ion 5 years ago, I got it for a good price because the (manual) transmission was bad - had a noticeable howl above 45 mph - all gears, clutch engaged or released. So the transmission was replaced with a very good used one, and a new clutch, pressure plate, slave cylinder, and master cylinder were installed, along with the hydraulic line which was rusted in place and got mangled on removal. The replacement line I found (possibly the last one available based on threads I've seen here) included a 'clutch hydraulic damper'. It was a large PITA to get the system properly bled, but eventually I did and everything was fine until spring of this year.

Fast forward to this spring. I was driving in town, had just left a stop light, and shifting into second, the clutch pedal went to the floor, and I lost all control of the clutch. I had it towed home, and two of my grandsons helped me tear it down. (I'm 80 now, not as spry as I was at 75 and could do it myself.) We found that the slave cylinder was completely blown apart. So we put in a new one and bled the system. It worked fine for a couple of days, then when driving, again in town, the clutch pedal got very firm and suddenly went to the floor, and I lost clutch control again.

I did some research and reading on the clutch damper, and it's supposed to keep clutch action 'smooth'. But other manufacturers have had problems with their dampers, and some have bypass kits for theirs. My grandsons came to help me again, and we found the slave cylinder had indeed blown up again. Fortunately, when I replaced the previous clutch line five years earlier, I had saved the hydraulic damper, so we installed that one when we put in the new slave cylinder (I couldn't figure an easy way to bypass the damper, as the connections were not compatible).

If the Vue is the same as the Ion, and the slave cylinder has perished, there should be evidence of brake fluid leaking out of the bottom of the transmission bell housing. If the slave cylinder does need to be replaced again, check to see if there is a device in the plumbing between the master cylinder and the slave cylinder - probably a hydraulic damper. If so, replace it. I'm not saying this is your problem, but the very firm pedal was the key indicator in my situation.