Though she remains credited all season, this is Patricia Wettig's final episode as Holly. She is the third original castmember to leave the series. The others were John Pyper-Ferguson (Joe Whedon) who left at the end of season 1 and Sarah Jane Morris (Julia Walker) who left at the end of season 3.
"I've Got A Mind To Tell You" by Spencer Day
"Twenty Years" by Augustana
Original International Air Dates:
Canada: Sunday, January 9, 2011 on Global
United Kingdom: Thursday, April 7, 2011 on More4
Australia: April 18, 2011 on Channel 7
Czech Republic: Sunday, February 24, 2013 on Universal Channel