The world’s longest-running play has come to Charleston. Experience the mystery and mayhem of this Agatha Christie tale. This classic story about four strangers snowed into a manor takes a turn for the worse when one of them shows up dead. Join The Threshold Repertory Theater to find out “whodunit,” but don’t tell, it’s a secret! Threshold Repertory Theatre, 84½ Society St. Thursday-Saturday, 8pm; Sunday, 3pm. $20; $15 senior; $10 student. (843)277-2172, www.charlestontheater.com