""I Can Only Imagine"" by the band MercyMe is the best-selling Christian song of all time. While lead singer Bart Millard wrote it in only ten minutes, it was a lifetime in the making. After his mom walks out, Millard (played in the movie by newcomer J. Michael Finley) endures years of abuse at the hands of his bitter father (Dennis Quaid), and uses music to escape. At age 18, Millard witnesses the transformative power of his faith when God begins to change his father's heart and heal their father-son relationship. Cloris Leachman and Trace Adkins co-star.