Loneliness
Bob is an American actor who is paid big money to do a whiskey commercial in Tokyo. He stays at a hotel and is seen at its bar nearly every night until he meets Charlotte, whom he takes an interest in. Bob is incredibly lonely even though he has millions of dollars and is well known over most of the world.
Running Away
A major theme of the film is running away, in the sense that there are responsibilities in life that we choose, and Bob has his in the form of his marriage and son. But Bob has chosen to run away from his issues rather than face them head on. He's taking the money rather than the hard road to find himself and it puts him face to face with Charlotte who becomes his muse for hope and a fleeting reality. Even in this relationship he fails as he betrays Charlotte by sleeping with the hotel jazz singer.
Midlife Crisis
This is a theme that enables Bob to go to Tokyo. He doesn't know who he is and what he wants after 25 years of marriage, and now he has found himself doing a commercial in Japan for $2,000,000 and seeking connection in any way possible. And he finds it in the form of Charlotte a young woman who is there for him in ways that more than likely he isn't for others, and others aren't for him.