Ok this has been driving me nuts for decades. I remember seeing a movie in the 80's that, for some reason, made a serious impact on me. I remember certain scenes but can't remember the name of the film. Here's what I do remember:

-a group of boys are searching for their father, who turns out to be kept in a cage by some monster

-during the search, there's a scene where one (or more) of the boys go under water but then cannot come out of the water anymore (the surface froze or otherwise hardened)

-There's a scene with hot air balloons

-I seem to recall that one of the character's name is or sounds something like "mice" or "mace"

If anyone can help, it would be much appreciated.