WGN America has renewed its latest critically acclaimed series, Underground, for a second season."With enormous pride we are announcing a second season of Underground, a series that has resonated with so many passionate fans across the country," said Matt Cherniss, president and general manager of WGN America and Tribune Studios. "It is an honor to have Underground on our air and we look forward to how the story will unfold in what is sure to be a stellar sophomore season."Mega Buzz: Empire's Jussie Smollett makes a pivotal decision on Underground.Set in 1857, the series follows group of slaves who make a daring escape from a Georgia plantation and embark on a 600-mile long journey to freedom.Underground has performed well for the network, increasing an average of 131% in ratings when a week of DVR playback is factored into viewership.To help promote the current season, the network is planning a marathon of its first season to air prior to the finale on May 11th.