Alles fließt

After Penny's homecoming from Nebraska, where she paid a visit to her family, she tells Sheldon and Leonard that their family has the flu. Sheldon is beside himself and is now afraid to infect with the disease. The next morning, Sheldon wakes up with a cough and it turns out that he is actually sick. When he says, "Leonard, I'm sick!", He calls for the apartment, so she does not have to worry about Sheldon. During his flight he is called by Sheldon. To get out of the affair, Leonard states that he is in the lab. Leonard then calls Howard and warns him of Sheldon's illness. Both of them take the decision to escape to the cinema together with Raj.

Since Sheldon can not make soup alone, he goes to Penny at the Cheesecake Factory to eat a soup. As he bothering the other guests, Penny has to go home with him, as Leonard, Howard and Raj are pushing for the job. At home, Sheldon does not want to be left alone because he is sick and so Penny stays with him in his apartment.

Meanwhile, Leonard breaks his glasses in the cinema and so he has to go to his apartment to get his reserve glasses. Armed with a mini camera and an impact sensor, Leonard sneaks into the apartment to avoid being noticed by Sheldon. At the end of the walk, he meets Penny, who immediately tells Sheldon that Leonard is now in the apartment and quickly leaves the house. Without his glasses, Leonard bangs his head and also has Sheldon's neck. In the end the two, Leonard with an ice bag and Sheldon with a quilt, sit together on the sofa.