Levin and his brother chat, but it's clear that the two men have very different interests and tastes.
Koznyshev, for example, thinks that District Councils (also called zemstvos) are important, and Levin does not.
Koznyshev wants Russia's zemstvos to bring freedom through representation to the countryside, but he feels that Russians are incapable of committing themselves to this kind of governance because they are too complacent and pleased over their failures. (These are Koznyshev's words, not ours!)
Then Koznyshev tells Levin that their older brother Nicholas (a.k.a. Nikolai) is back again.
Nicholas wasted all his fortune, and he's not on good terms with his brothers or with Russian society.
Koznyshev got a note from Nicholas, asking his brothers to leave him alone.