Leonard and Stephanie are supposed to be having a nice quiet romantic dinner at his apartment, but Sheldon has joined them because he doesn't want Leonard to mess things up. Sheldon is particularly happy with Stephanie because he wants her to be McCoy in their "Star Trek" group.
Leonard and Stephanie are at the movies when Sheldon comes in and interrupts. He makes a comment about Leonard's cryptic invitation, and when Leonard asks him to elaborate, Sheldon says the note Leonard left said "going to the movies" but didn't indicate which movie at what time at which theatre, and Sheldon said he had to go through Leonard's history on his web browser on his computer to figure it out, to which Leonoard looks at him kind of scared. Sheldon then goes around to various seats making weird noises to find the best acoustic seats - only to discover that Leonard and Stephanie are right in them. It was funny to watch the other people in the theatre stare at Sheldon as he made his weird noises. I don't even know what I'd think if I were to encounter him, but I'd certainly never agree to go to a movie with him if I knew that he did that sort of thing.
Of course, Sheldon has no idea that his efforts to "help" are actually setting up obstacles that Stephanie and Leonard have to overcome.
Sheldon goes to Penny's to ask her what went wrong with her relationship with Leonard so that he can be sure Leonard doesn't do that with Stephanie. Penny proceeds to tell him a story - which is actually the plot of "The Lake House" - which Sheldon says Penny forced him to watch. Later on, Sheldon apologizes for asking inappropriate questions of her and tries to start again - but when he asks about her menstrual cycle, she shuts the door in his face.
I did think it was funny but hadn't noticed before that Sheldon does the "
Sheldon is again interrupting a dinner between Leonard and Stephanie, and Sheldon tries to make Leonard appear to be a big strong man by having Leonard open a jar of something for him, but Leonard can't and ends up breaking the glass and cutting himself, and they all go to the hospital so Stephanie can stitch him up. Stephanie tells him that she doesn't mind that he cried, even though he denies crying.
Leonard has an account on Facebook, and he discovers that Sheldon has hacked into his account and changed his status to "taken". Leonard thinks that might be too fast and worries about what Stephanie thinks, until the others show him that Stephanie has also changed her status - to indicate that she's now dating Leonard.