The Big Bang Theory season 9
The Big Bang Theory season 9's official posterCBS

Secrets will be revealed in The Big Bang Theory season 9 episode 20 after Amy (Mayim Bialik) convinces Sheldon (Jim Parsons) to join Leonard (Johnny Galecki) and Penny (Kaley Cuoco) for a weekend camping trip into the wild to conquer his fears. The episode titled The Big Bear Precipitation, which will air on 7 April at 8pm ET/PT, will also see Sheldon getting paranoid over trivial matters and Raj's (Kunal Nayyar) overdoing on his pregnancy gifts.

The official synopsis for the episode reads: "Secrets are revealed when Leonard, Penny, Sheldon and Amy go on a weekend getaway. The Big Bear Precipitation — Sheldon spills a secret of Leonard's when the two take a weekend cabin trip with Penny and Amy. Also, when Raj goes overboard with pregnancy gifts, Wolowitz and Bernadette must draw the line."

Warning: Spoilers ahead

According to a leaked report, it will begin to rain soon after Amy, Sheldon, Leonard and Penny reach the cabin and everyone, apart from Sheldon, gets upset since they cannot go on a hike. Leonard then suggests that they play board games, when Sheldon points out that the games are incomplete with the Jenga missing pieces and the Scrabble having only seven tiles.

The girls then suggest building a fireplace, as the men begin to discuss the science of it. When Penny flips on a switch to bring the fireplace to life, Leonard goes: "Scientists invented that you know...".

In another scene, Howard (Simon Helberg) is seen asking Bernadette (Melissa Rauch): "Are you... REALLY sure that he [Raj] isn't going overboard with this [on the pregnancy gifts]?" As soon as Bernadette replies in the negative, Raj appears with a "giant ass teddy bear". "You saw him with that thing, didn't you?" Bernadette asks, to which Howard replies: "Astronauts could've seen that."

Click here to watch the episode via live stream online on CBS. You can also click here to watch it online (only in the US).