THE GRAY MAN isn't the complete story of serial-murderer Albert Fish. It's mostly about his encounter with young Grace Budd in 1928, and the ensuing horror of that case. Fish's biography, as well as his unspeakable crimes, are well documented elsewhere.
This is presented as more of a cat and mouse police procedural / drama. Patrick Bauchau is quite good as Fish, a seemingly kind, gentle old man with astoundingly vile proclivities. A first-rate psychological thriller, TGM is also a useful starting point for anyone interested in further pursuing the exploits of this very disturbed / disturbing man...