The Door

Sometime in 1986, or maybe 1987, in the dead of night, a man parks his motorcycle next to an empty amusement park. He hides from security guards as he finds his way to a block of flats and enters one. A guard smashes a window and yells at him to leave. He does, but he's carrying something from the flat. He is Nikolai, married to Anya, the father of Lena, who is a thin, ethereal waif. In what we later learn is a flashback, we see them packing to leave, hurried by authorities, who tell them to leave everything behind. What's going on, why can they bring nothing? And why would Nikolai return home, sometime later, to steal a door?