The gang watches Howard practice pitching via video game baseball because he's been chosen to throw the first pitch at a Los Angeles Angels game. 

Sheldon and Amy return from a dinner date. Sheldon invites Leonard and Penny to join them the following night on a double date.

Sheldon tells Leonard and Penny he believes he and Amy have a superior relationship to them. Leonard is annoyed that Sheldon always has to be the best at everything. Penny wonders why he cares so much.

Amy asks when Penny and Leonard are getting married. She says she wants to wait long enough so no one thinks she pregnant. Sheldon shows them a test that calculates the strength of a relationship. He and Amy have scored an 8.2. Leonard wants to take it, but Penny doesn't and walks off upset. 

Leonard goes to talk to Penny who says she scared because they're engaged and have nothing in common. He admits that scares him too. 

Leonard and Penny return to the table and now Penny wants to take the test and Leonard doesn't. He says it doesn't matter what the test says. Amy is jealous of their romance. 

Bernadette and Raj go to the gym with Howard to help him prepare for his pitch. Howard is in shock by how far home plate is from the pitchers mound when they measure sixty feet in the gym. Howard is throwing his pitches, but not getting anywhere close to Bernadette who is playing catcher. 

Howard talks to Mike the astronaut on his laptop to ask for advice. His advice is not to do it. There's no upside and tells him in space he couldn't even toss him a pen and that was in zero gravity. 

The gang all come to the game to watch Howard throw the pitch. Howard gives a speech about how he couldn't throw a pitch, so he practiced, but realized that he's a scientist. So, instead of throwing the pitch he unveils a working prototype of the Mars Rover. It moves extremely slowly and Howard admits he didn't think this through. Everyone boos him as the Mars Rover inches across the field towards home plate.