Keats begins by wishing he could escape from the real world and hide away in the world inhabited by the immortal nightingale. Finally he decides that he will attempt to do so by flying there "on the viewless wings of poesy," that is, in his imagination. In the poem he succeeds immediately in realiziing his wish. The beauty of the poem is mainly in the description of the nightingale's world as Keats imagines it. The poem is dramatic because of the author's motivation and his partial success in achieving his goal. The reader identifies with the poet because he too would like to escape from reality, at least for a while. F. Scott Fitzgerald borrowed the line "tender is the night" for the title of his best novel.
Keats manages to maintain his illusion that he is with the bird up until the famous lines
Charm'd magic casements, opening on the foam
Of perilous seas, in faery lands forlorn
But then he finds himself being recalled to the world of reality and has to bid the nightingale adieu.