‘Big Bang Theory’
How will Sheldon (Jim Parsons) react when he finds out Leonard (Johnny Galecki) is doing something behind his back in “Big Bang Theory” Season 10, episode 15? CBS

“Big Bang Theory” Season 10, episode 15 will see Leonard (Johnny Galecki) and Howard (Simon Helberg) leaving Sheldon (Jim Parsons) out of their plans.

In “The Locomotion Reverberation,” the two friends will try to make some changes on their invention without Sheldon’s help or input. The latter will soon find out that they’re doing something behind his back and gets upset. Sheldon always wants to be involved and in the know, not only with their inventions, but also with the lives of all of his friends. Leaving him out of their discussions, plans and decision will definitely cause him to flip.

Elsewhere, Bernadette (Melissa Rauch) will finally have the chance to go out with her friends, Amy (Mayim Bialik) and Penny (Kaley Cuoco). After giving birth to her daughter, Halley, Bernadette has been a hands-on mom. She’s been having sleepless nights because of Halley’s nonstop crying, so some time off with Penny and Amy will be good for her. But Bernadette’s night out with friends could only mean Howard (Simon Helberg) will be left all alone to watch over their baby. Luckily for him, Raj (Kunal Nayyar) is always at his beck and call.

Prior to episode 15, “Big Bang Theory” Season 10 will first go on a week-long hiatus and will return with episode 14 on Feb. 2. Episode 14, titled “The Emotion Detection Automation,” will focus on Sheldon using a machine that helps him detect and understand all sorts of emotions. In the same episode, Raj will reunite with his four ex-girlfriends, and each one of them will have something to say about why their relationship with him failed.

Episode 14 will also see the return of Penny’s brother, Randall (Jack McBrayer). Penny will try to hook Randall up with a job interview, but she soon realizes that this could cause a lot of problems. After all, Randall used to be a drug dealer.

“Big Bang Theory” Season 10 airs Thursdays at 8 p.m. EST on CBS.