Perhaps you've heard of Winter's Gem, and of the tragic fate of the Lady Karina. And perhaps not. It is, after all, a tale unspeakably old. Yet the Earth does not forget, and those of us who guard it do not wither...
Nine thousand years she has slumbered, while Winter diminished. So obsessed was He in her care, that He allowed Summer to run unchecked. His power dwindled, and Summer grew. There is a great unbalance in the world, young ones. One that I fear will break the back of the Earth itself, if not addressed. Winter must return. It is the Way.
A real-world location fit for filling out your adventure; where norse icelandic fishermen suffered unthinkable conditions throughout frigid winters to harvest the fruits of the ocean.
In the summer there is a small stone jail for those who are caught breaking the rules of the Sorcery Springs Geyser Basin, but in winter they are imprisoned within the warm waters themselves. No bolts or bars are needed, the cold takes the place of prison walls.
One thing you must realise is that there is no such thing as pure iron/steel these days. Iron/steel isn't nearly as strong now as it was in medieval times. However, with that said, iron in early medieval times was so soft you could hack right through a helm with a sword and leave a nice lil mark on the skull (depending on the grade of iron used on the sword and the helm, ofcaurse). After many hundreds of years of fine tuning, however, the only use the sword had was to puncture the plate. That was very difficult, however, since the grade of steel was so hard... only blunt instruments and weighted axes had any use against plate armor in later medieval times. Makes me wonder why rapiers were so popular then and why less people wore plate (Other than it's obsene costs... a nice suit of armor would cost as much as a nice lexus does now... and a kings suit would be as much as a rols royce).