One night in a shabby bar Helena meets a little girl whose father begs money for drink by getting his daughter to sing for his cronies. Helena takes pity on the girl and assists her in her performance. The girl attaches herself to her saviour and follows Helena. All night long, through the night-time streets of modern-day Helsinki, Helena flees the strange girl. The girl inevitably finds her, until it finally dawns on Helena that she is actually fleeing from herself. The girl is her mirror, and she recalls the little Helena, who was also abandoned and exploited.

The twins Helena and Irene are born in Helsinki toward the close of the Second World War. A few months later, their mother Sirkka leaves them in the care of their grandmother, an old Communist, and flees with a German soldier to central Europe. Their grandmother calls the girls Vladimir and Ilyich, after her paragon Lenin. From an early age, Irene is beautiful and admired, while Helena keeps her distance. Their life under the protection of their grandmother and her Communist teaching ends with her sudden death.

At the age of eight, the girls find themselves in a children's home. There they create a world of their own, excluding all others. They are like two halves of the same person. This symbiotic love accompanies them throughout their lives.

One chill autumn day their mother Sirkka appears in the yard of the children's home. She is accompanied by Ramon, a Spanish trapeze artist. Helena observes as Ramon bends and stretches the limber and lovely Irene. He wants her for his circus. However, the matron of the children's home forces them to take Helena as well.

On a circus tour of central Europe, Ramon instructs the unwilling Irene. Sirkka worships Irene. She teaches Helena that life consists of the gifted and those who serve, and that Helena's task is to grow into a fitting servant for her sister. Thus has her mother succeeded by serving gifted men. Helena humbles herself during the daytime, but in the still of the night the girls return to their world of mutual affection, a world from which even their mother is excluded.

The gruelling work quickly wearies Irene. She falls from a great high. She is not hurt, but her mind is injured. She no longer speaks or wishes to use her legs. It is the mid-50s and the circus troupe has arrived in Hungary. The mother and daughters are no longer of any use to Ramon and he vanishes into the chaos of the Hungarian anti-communist revolts. Resorting to an old trick, Sirkka take advantage of a Russian officer and prepares to make her way by train to Finland.

Aboard the train, Helena reveals that she has secretly learned the fire-eater's art. For the first time she is granted her share of her mother's admiration. The three of them tour construction sites in northern Finland in a rattletrap bus. Helena spews fire while her mother and Irene assist. Covetous, drunken eyes stare at the half-naked body of the now maturing Helena. After one performance, the girls find their mother sleeping with an old derelict. For Irene, the eternal sleaziness of such a life is unbearable. She runs to the forest and toward black water flowing beneath the ice of a vernal river. Helena saves her. She acquires the burden of both her mother and her sister. But eventually life brutally separates them.

At night in present-day Helsinki, Helena ceases her attempts to escape the unknown girl. She now follows her. Helena, having looked into her past, relinquishes her hatred of herself and for the first time now wishes voluntarily to assume responsibility for another human being.