A new planet four times the size of the moon, appears in the sky of Earth. Searching for it out her car window, a young woman (Brit Marling) causes a car crash, killing a mother and child and sending the father (William Mapother) into a coma. After he emerges from the coma, she contrives to work as his housecleaner, and they develop a fragile relationship without him realizing who she is. The presence of Earth 2 in the sky suggests alternative lifelines we could have lived. Marling makes an impressive debut, and the film is thought-provoking. - Three and a half stars