After both of their marriages fail, Oscar Madison and his uptight, former college roommate, Felix Unger, decide to live together.

Felix tries to help after Oscar is hired to ghostwrite a retired baseball player's autobiography, but he ends up making the task more difficult.

After Oscar realises he forgot Felix's birthday, he tries to impress Casey by planning an impromptu surprise party.

Dani worries about being the only single person at her high-school reunion, so Oscar and Felix employ their unique strategies to help her find a date.

While attending the wedding of a friend from college, Oscar hopes to reconnect with an old flame while Felix wants to show his ex-wife that he is a changed man.