Penny and Leonard had a bittersweet wedding, while Sheldon and Amy went completely off the rails on The Big Bang Theory season 9 premiere, “The Matrimonial Momentum.”

Here comes the bride

Leonard and Penny wait their turn to get married in Las Vegas, and decide to livestream the wedding for everyone back in Pasadena. Leonard is on edge, concerned that Penny may be having second thoughts about their decision, given the revelation that he kissed a female scientist on the North Sea.

For her part, Penny is pretty calm about the whole thing. While it’s partly her lack of emotion that gets Leonard riled up, Penny seems to be handling the situation well… at least for now.

Finally, the two are in front of the preacher. Leonard reads Penny his vows, a moving scientific metaphor that adds a flavor of destiny to the admittedly dinky ceremony. Penny delivers an off-the-cuff vows that turns into a recitation of “You’ve Got a Friend in Me.”

It seems like this might be a bust, but it turns out that Leonard loves Toy Story. It’s lovely to see how well Leonard and Penny can make each other happy, just by playing to their strengths.

Take me or leave me

Back in Pasadena, the rest of the gang gathers at Howard and Bernadette’s to watch Penny and Leonard’s livestreamed wedding. Insistent on returning things to his definition of “normal,” Sheldon crashes the party and makes everyone uncomfortable by loudly discussing his and Amy’s floundering relationship.

As Penny and Leonard say their vows, Sheldon demands that Amy make up her mind about their breakup. Frustrated, insulted, and upset, Amy has had enough.

“You’ve made the decision easy,” she tells Sheldon. “We’re broken up.”

True confession

In their hotel room, Leonard and Penny start to kick off their wedding night. Unfortunately, kissing makes Penny freeze up, imagining Leonard kissing the other girl. Leonard insists that the kiss was drunken and not romantic, and that he feels guilty “every time he sees her.”

Penny is like, say what now?

Leonard is forced to confess that he still works with the woman. Penny is furious, though Leonard says he didn’t tell her because she had closed the conversation.

Either way, any hope these two had of a happy wedding night goes straight out the window.

Bad blood

Meanwhile, Sheldon tells his mother that he and Amy are broken up. He wants to send the wedding ring – his grandmother’s – back to her, but Mrs. Cooper insists he keep it. (Hopefully, Mrs. Cooper is wiser about this relationship than “Shelly” is.)

Leonard and Penny return home and storm off to their separate apartments. Sheldon tries to help by bringing Penny tea, but reveals that the lady scientist – Mandy Chow – is both brilliant and beautiful.

Then Penny admits that she advised Amy to “do what makes her happy” with regard to Sheldon. “It’s not my fault you’re a bad boyfriend!” Penny says, adding another dimension of anger and hurt feelings to this smarting quadrangle.

Later, Sheldon and Leonard sit glumly in their apartment. Leonard feels guilty, and depressed that he is spending his wedding night with Sheldon.

“I never imagined it any other way,” Sheldon says.

What did you think of ‘The Big Bang Theory’ season 9 premiere?