Freeman Williams’s review published on Letterboxd :
The conclusion of Bergman's powerful film trilogy finds the director leaving the themes of his earlier films, dealing with daily tragedies in a fairly realistic manner, to more existential terror, struggles in the landscape of the mind.
Two sisters, returning home by train, must stop in a European town when the elder sister's disease - possibly tuberculosis - reaches a crisis stage. This elder sister sits in the hotel room, her disease ebbing and flowing, while the younger goes out on the town in search of sex, and her young boy roams the halls of the curiously deserted hotel, the only other occupants a troupe of performing dwarves, and a kindly elderly waiter.
They do not speak the language of this country, presented as gibberish, even in signs and newspapers. There is much hidden history between the two sisters, which is never made overt; there is the possibility that the boy is actually the son of the older sister. Tanks roar through the city in the middle of the night.
This is a movie to be picked apart and discussed; it is not a passive experience. At all.