'The Big Bang Theory' season 9 finale spoilers, plot news: Leonard's dad attends son's second wedding with Penny in episode 24

Penny (Kaley Cuoco) and Leonard (Johnny Galecki) decide to remarry in front of friends and loved ones in "The Big Bang Theory" season 9 finale. As expected, it won't be smooth sailing, especially with the Hofstadters around.

Leonard's parents will be attending the wedding set to take place in season 9 episode 24 titled "The Convergence-Convergence." Beverly (Christine Baranski) is going to be there but will be furious to learn that Leonard's dad Alfred (Judd Hirsch) was invited too.

According to spoilers, Alfred and Beverly will have a hard time standing each other's presence and will not have anything nice to say to each other in "The Big Bang Theory" season 9 finale, potentially ruining Leonard and Penny's second wedding.

On the other hand, Sheldon also invited his mom Mary (Laurie Metcalf) to the wedding. Like Alfred, she isn't very fond of the Hofstadter matriarch, and this will lead to the two getting along and eventually hooking up. 

As "The Big Bang Theory" fans would imagine, their sons will be the least excited about this development. It will be exciting to see how they react about this.

As the wedding mayhem ensues, Howard (Simon Helberg) will be busy with his project at the engineering lab with Raj (Kunal Nayyar). In the season 9 finale, he will successfully make it work.

Before he can rejoice in his achievement, he will receive an email from the Air Force and make him believe that his new invention got him in big trouble with the government.

On a side note, this episode will be the first time Leonard's father will appear in "The Big Bang Theory." Meanwhile, it will be the third time this season that Baranski will appear as Beverly.

"The Good Wife" star's second appearance will take place in episode 23 "The Line Substitution Solution," which will air on May 5.

"The Big Bang Theory" season 9 finale "The Convergence-Convergence" will air on May 12 at 8 p.m. EDT on CBS.