In tonight’s Big Bang Theory, “The Locomotive Manipulation,” Amy and Sheldon discuss Valentine’s Day. Amy suggests going to a bed and breakfast at Napa Valley. Sheldon doesn’t like the idea of eating with strangers, so Amy tells him that Bernadette and Howard will be there. He then points out that he and Amy shouldn’t be in the same room together, since they have only been together for three years and people might talk. Amy only convinces him to go when she reveals that they will be having dinner on a fully functioning vintage train.
Leonard and Penny decide not to go to Napa. Leonard comments that it probably isn’t a good idea to bring Penny where wine comes from. Raj asks if Penny and Leonard will watch his dog, Cinnamon. Penny is shocked that he has Valentine’s Day plans. He admits that he doesn’t, he just reserved the use of the big telescope.
Penny brings Leonard flowers and chocolate and Leonard gives her Laker tickets. He tells her that she can bring someone that will actually enjoy the game with her. After Penny and Leonard return to the living room after having some alone time, they find that Cinnamon ate the chocolate. They decide to bring her to the vet right away.
On the train, Sheldon asks the waiter questions about the train rather than the food. A man sitting behind Sheldon answers his question for him instead. Sheldon goes to sit with the man who answered his question, and the two of them bond. Amy is unhappy that he is not with her. Bernadette goes over to Sheldon and yells at him for not spending time with Amy. Sheldon realizes that he was insensitive and goes back to the table, but not before he invites over his newfound friend.
The vet asks Penny and Leonard questions about the chocolate the dog ate before Raj bursts in, yelling at Leonard and Penny. The vet says it is a good sign that she is not throwing up, and she is going to take her in the back to give her something to rid the toxins. Raj suggests that she should sing her Katy Perry.
Sheldon and his friend continue to speak about trains, boring everyone. Bernadette tells Amy that she helped to mold Howard after she met him and that eventually, she will be able to do so with Sheldon.
Raj is happy when he finds that he will be able to bring home Cinnamon, and there seems to be a vibe going on between the vet and Raj.
Amy confronts Sheldon, telling him that he is being rude to her. Sheldon argues that he could not possibly be rude since he hasn’t spoke to her since they got on the train. Amy points out it is Valentine’s Day and Sheldon says Amy promised that it would be a trip they both enjoy. Sheldon goes off on a tangent about typical romantic things and during his rant he stops and gives Amy a long kiss, which he seems to enjoy. He then invites her to the engine room, but on their way there, Sheldon’s buddy starts to tag along again.
Raj looks at the note the vet gave him, which was supposed to have care instructions. The note instead says that she had a great time with Raj and she gave him her phone number. It also says her name is Yvette.
Sheldon comes home and starts to tell Leonard about everything he did on the trip, including kissing Amy, much to his surprise. Leonard asks him if he could pick out of all the things he just listed, which his favorite was. Sheldon doesn’t give a concrete answer, saying he would need additional data.