Sheldon and Amy have decided to take their relationship to the next level... by purchasing a pet together, namely a turtle. That step takes a giant leap backward when Sheldon divulges that he has submitted an application to be among the first people to colonize Mars, something he did not discuss with Amy before doing so. She is more upset by the fact that it was a unilateral decision on his part than by the decision itself. Is there any way Sheldon can make it right with her? Meanwhile, Leonard gives Penny a late Valentine's Day present that he bought at the sex shop: body paint and canvas so that they can make their own painting using their naked bodies as the brushes. Both the process and the final product aren't quite what they were expecting. And Emily is called on a short emergency to the hospital leaving Raj alone at her apartment. He does something that might end their relationship, with Howard and Bernadette not providing much help or guidance on how to fix the problem, both figuratively and literally.