Big Bang Theory season 9
Amy, Penny, Howard, Bernadette and the rest of group in The Big Bang Theory season 9 episode 6 CBS

Sheldon and Leonard will make a trip down the black market to buy helium, in the upcoming episode of The Big Bang Theory season 9. Episode 7 is titled, The Helium Insufficiency, where Penny and Bernadette download a dating app on Amy's phone.

In the midst of a nation-wide helium shortage, Sheldon and Leonard take desperate measures to get the supplies they need. Also, Penny and Bernadette download a dating app on Amy's phone to try and find her a new man, on The Big Bang Theory. Michael Rapaport guest stars Kenny, a black market dealer.

According to a leaked report, Sheldon and Leonard learn that Swedish scientists are trying to steal their "Superfluid Helium" idea and they try to obtain some helium from their colleague Barry Kripke, but return unsuccessfully. Later they take desperate measures and meet Kenny (guest star Michael Rapaport), a black market dealer.

In the latest promo, the voice-over says, "Physicist need Liquid Helium, and they need it now." Which is followed by Leonard and Sheldon discussing their low helium supply. Howard, however, has a idea and says, "I know a guy. If you don't ask too many questions." And soon, he's bombard with questions like, "Who is he? Where does he work? How did he get the Helium?"

The two -- Leonard and Sheldon -- finally meet the dealer, but as usual their conversation does not go too well, thanks to Sheldon's quirky ways. Leonard tells Kenny, "Hi, I am Leonard, this is my friend," who immediately introduces himself as "Skippy".

The guys try to bargain with the dealer, who says, "No money, no helium." He claims that their discussion is going nowhere, when Sheldon points out, "Not necessarily. You can kill us... really. You are only limited by your own imagination." As a scared Leonard remarks, "What are you doing Skippy?" Hinting that he is trying to get them killed.