The Cabinet features the magical mountebank Caligari who commands a clairvoyant murderous somnambulist Cesare. When Cesare correctly forecasts Francis' friend's death, then tries to run away with Jane, Francis' fiance, Francis pursues Caligari. Cesare dies along the way, while murder, confusion and doubling take over, not to mention all the crooked doors. The entire set is askew, which, along with the half light/half shade dichotomy of the lighting, makes the film look like a disturbing dream in which even gravity doesn't work right.
I'm a bit fuzzy on the plot, with its multiple layers of mania and mistaken identity, but I do like its examination of the man called Caligari. He consciously decides to reinvent himself in the style of a mythical monk who could command a sleepwalker so that the sleepwalker acted as his golem. The motivation of the Caligari wanna-be, however, seems murkier, with sexual, even sadistic, components. When Cesare is first admitted to the mental hospital where wanna-be Caligari is the director, Caligari rejoices, caressing the inert man with a demonstrative, lascivious affection that reminds me of, say, Nosferatu reaching for Ellen. Caligari seems to want control over Cesare as much as he wishes to possess Cesare in an inert, doll-like state to care for him, objectify him and quite possibly desire him. Note that the wanna-be's reaction to Cesare's death looks very much like a stereotyped silent film husband's reaction to seeing the corpse of his dead wife. I humbly submit that there are sadomasochistic homoerotic tensions at work in this film which, along with the slippage of identity, make it all the more interesting.