'Big Bang Theory' season 9 spoilers: Sheldon and Amy spend Thanksgiving together in episode 9 'Platonic Permutation'

Sheldon (Jim Parsons) and Amy (Mayim Bialik) hangs out at the aquarium in 'The Platonic Permutation' episode of 'The Big Bang Theory' season 9.cbs.com/shows/big_bang_theory

Can Sheldon (Jim Parsons) and Amy (Mayim Bialik) regain their friendship after failing as a couple, as they spend Thanksgiving together in the next episode of "The Big Bang Theory" season 9?

In the episode titled "The Platonic Permutation," Sheldon and Amy will try to go back as friends as they hang out at the aquarium for Thanksgiving. This is a bold move from the former lovers, since they have not exactly been in good terms since the start of the current season after they broke up in season 8 finale.

Sheldon has been on a downward spiral all throughout the season, while Amy moved on and dated Dave (Stephen Merchant) for a while before they broke up in the previous episode. Sheldon also tried to start dating again by asking the gang to set him up with another woman, but he decided not to push through with it when his time allotment ended.

However, the result of their trip to the aquarium is not revealed in the promo clip for the episode.

Meanwhile, their friends Howard (Simon Helberg), Bernadette (Melissa Rauch), Raj (Kunal Nayyar) and his girlfriend Emily (Laura Spencer) will spend their Thanksgiving holiday at the soup kitchen as volunteers for goodwill, in spite of Howard's reluctance at first.

In this episode, the gang will meet the Hyperloop inventor and business magnate Elon Musk, who has also decided to spend his Thanksgiving at the soup kitchen. Howard will even share a slice of pumpkin pie with him during their break from the dishwashing duties.

Elsewhere, Leonard and Penny will spend their first Thanksgiving together as a married couple. But Penny will be surprised to find out that her husband knows a lot more about her than she expected.

The official synopsis for the episode reads:

"Sheldon and Amy try hanging out as friends when they spend Thanksgiving together at the aquarium. Also, Wolowitz reluctantly agrees to volunteer at the soup kitchen with Bernadette, Raj and Emily, and Penny discovers that Leonard knows more about her than she thought."

"The Big Bang Theory" season 9 episode 9 airs on Thursday, Nov. 19, on CBS.