PORTLAND, Maine — René Johnson’s one-woman, interactive storytelling show is not a free ride. Johnson challenges the audience to speak to strangers in the room. She has them gaze in each other’s eyes in silence. She asks them personal questions. Johnson expects the audience to participate and pull its own weight. It’s the least they can do while she unravels harrowing and intimate details of her life.Through multiple characters, dance and song, she weaves a story of escaping South African apartheid, childhood abuse at the hands of her mother, teenage self-harm and coming to terms with Maine’s own racism. Johnson, 33, will perform her show three times this weekend at Bright Star World Dance studio on High Street. She first devised the piece during a summer program at the Celebration Barn Theater in South Paris in 2013.