When Louis Ives (Paul Dano) heads for New York City and rents a room in the madly discombobulated apartment of Henry Harrison (Kevin Kline), a failed but brilliant playwright, the two men, separated in age by more than 40 years, develop a relationship as irascible mentor and eager apprentice, which leads to a series of urban adventures - encountering everything from a leaping lion to a wildly jealous hirsute neighbour to drunken nonagenarians and an entrancing green-obsessed young journalist (Katie Holmes).