The University of Southern Maine Department of Theatre is staging the English-language premiere of In the Underworld, a dark, yet humorous and ultimately inspiring operetta written by a female member of the French Resistance while imprisoned in a concentration camp. Performances take place April 18 through April 27 at Russell Hall, on USM’s Gorham campus (37 College Ave.); today at 5 p.m. Tix: $15 ($11 seniors, $8 students). 780-5151. usm.maine.edu/theatre.