Those opening scenes of mushing through snow under arctic conditions made me appreciate the comforts of an easy chair and fireplace. It's an oddball Western from start to finish with a strong cast and a noirish atmosphere. Essentially a band of escaped convicts invade a small mountain village whose men are away leaving only the women. As you can guess a number of subplots evolve from the premise, the most important of which has Glenn Ford trying to clear himself of an unjust murder charge.
I love it when evil-eyed bad guy Jack Lambert has a stare-down with gimlet-eyed bad guy Zachary Scott. It's almost like a couple of Darth Vaders squaring off. There are a number of good scenes most of which involve Scott, especially when he's vamping the hapless Ann Dvorak. But, the best scene defies our expectations when the two youngsters run off to the woods. It's a chilling, well done sequence. The cast is almost an A-list, with Ford quite good as the resolute Jim Canfield when he stands up to the other four convicts. Ditto, the other performers who manage to make some difficult dramatic scenes convincing enough.
And catch that ending. It made me wonder just what does comprise a "duly constituted jury". It's an unusual resolution for its time, to say the least. I don't think I ever found out the "Secret" of the title, nor I believe do we ever see Convict Lake. Nonetheless, there's more than enough going on to fill a lively 83 minutes, and I agree with the others that the movie is generally an under-rated Western.