On The Big Bang Theory Season 10 Episode 20, Leonard talks about his plans to work with Sheldon and Wolowitz on their project, but Amy is concerned because she has plans to work with Sheldon that day as well.

Sheldon explains how he plans to have the time to work on both projects on the same day.

Sheldon seems to be handling it well, but pushes himself too hard and gets sick.

Meanwhile, Bernadette is preparing herself to go back to work since her maternity leave is almost over, and she's emotional about leaving Halley. She confides in Stuart but asks him not to tell Howard.

Sheldon wakes up on the couch to find his friends watching over him, and he realizes he has no idea what happened to his day, though he does remember taking cold medicine.

He panics when he realizes he's not only missing his pants, but he's also missing his notebook with classified information.

Bernadette tells Howard why she's upset, and admits she doesn't know if she should go back to work or not.

He and the others set out to figure out what Sheldon did. They find themselves at a cowboy bar, which is where he left his notebook.