On Kates wedding day to Phillip, Rebecca shows signs of deterioration.

Meanwhile, Beth and Madison investigate a Kevin romance mystery.

The themes of the stories: routine and music.

THIS IS US – “Day of the Wedding” Episode 613 – Pictured: (l-r) Mandy Moore as Rebecca, Chrissy Metz as Kate – (Photo by: Ron Batzdorff/NBC)

Ron Batzdorff/NBC

But first things first, the Pearson matriarch.

Rebecca

In the flashback, Rebecca’s morning starts with robotically packing the kids' lunches.

Then, she goes for a haircut.

THIS IS US – “Day of the Wedding” Episode 613 – Pictured: (l-r) Susan Kelechi Watson as Beth, Sterling K. Brown as Randall, Jon Huertas as Miguel, Justin Hartley as Kevin, Mandy Moore as Rebecca, Chrissy Metz as Kate, Chris Geere as Phillip, Griffin Dunne as Nicky, Vanessa Bell Calloway as Edie, Adam Korson as Elijah, Kellan Tetlow as Nicky, Caitlin Thompson as Madison, Callie Carlin Ogden as Franny – (Photo by: Ron Batzdorff/NBC)

Ron Batzdorff/NBC

However, Rebecca regrets the decision, and shamefully shows Jack when he returns home from work.

Jack eventually asks why she did it.

She wants to remember surprises can still happen.

As an example, he challenges her to play the restaurant’s piano.

She accepts, and delivers a gorgeous ballad.

In the present, on Kate’s wedding day, Rebecca’s cognition has clearly deteriorated substantially.

She keeps commenting about Jack coming, and intermittently referring to Kevin as Jack.

Here’s the chorus to the song (by composer Siddhartha Khosla) of the hour.

If there’s a right way to say it,

I’m still learning how.

All that we have is a forever now."

And … with that, time for the rest of the episode’s excitement.

She admits she’s nervous about Rebecca’s performance.

She fears Rebecca’s devastation if she can’t manage it.

He steps up big time, and helps ensure his day with Kate is happy as can be.

It’s all we could want for our Bug.

Miguel and Randall

In the present, Randall just became senator.

When he hears her ask about Jack that morning, he gravely checks her medicine.

Randall obliges, but throughout the tasting, he won’t stop reflecting on his mother’s condition.

He wanted one hour to drink wine, with Randall, and feel like a normal human.

Miguel notes things are happening so fast, clearly overwhelmed by managing Rebecca’s situationandhis own.

Randall looks apologetic but still doesn’t shake his grieving-Rebecca-mentality.

His wedding toast later is depressing (and long).

Ever the magician, Beth drags him out of the funk and onto the dance floor.

The ladies then notice a bra and floral wrap, and excitedly conclude Kevin slept with someone.

Here, we get thefantasticcomedic duo we didn’t know we needed Madison/Beth spinoff like?

They soon learn the floral wrap belongs to Cassidy, so they think it’s her.

He says it’s long and he’s not yet sure if it’s good.

Let’s make like Beth and Madison and detect.

Here’s to a coming answer!