The several hours-extended romance culminates in a pretty night in the park and an open-ended dilemma about the couple's future (which is answered in subsequent motion pictures, for inquiring minds). It's romance. It's sci-fi. What tends to make it attractive: When a spouse (Julianne Moore) thinks her partner (Liam Neeson) is dishonest, she hires a simply call girl (Amanda Seyfried at her absolute sexiest) to try out to tempt him.