As the Fugue String quartet approaches its 25th anniversary, the onset of a debilitating illness to cellist, Peter Mitchell (Christopher Walken), forces its members to reevaluate their relationships. After being diagnosed with Parkinson's disease, Peter announces his decision to play one final concert before he retires. Meanwhile the second violinist, Robert (Philip Seymour Hoffman), voices his desire to alternate the first violinist role, long held by Daniel (Mark Ivanir). Robert is married to Juliette (Catherine Keener), the viola player of the group. Upon discovering Juliette does not support him in this matter, Robert has a one-night stand. Further complicating matters, their daughter, Alexandra (Imogen Poots), begins an affair with Daniel, whom her mother once pined for. Yet bound together by their years of collaboration, the quartet will search for a fitting farewell to their shared passion of music and perhaps even a new beginning.