This song develops the characters of Hodel, and to a lesser extent Perchik, and Tevye.

We learn Perchik did not ask Hodel to join him in Siberia, but she will be joining him anyway, because the need to be with Perchik outweighs her desire to stay in Anatevka, the home she loves.

Perchik is being held in a Siberian prison camp. Unfortunately, the primary resources for Siberian Prison Camps often leads to USSR Gulags. As we want Dostoevsky's Kartoga Experience (pre-1917 revolution), not Solzhenitsyn's Gulag Experience (post-1917 Revolution), please see this article to understand Dostoevsky's literal experience.