All Barry and Kara needed was love.

That's what the not-so-villainous Music Meister wanted to teach the superheroes on The Flash Season 3 Episode 17 "Duet."

And obviously the only way to do that was for him to trap the speedster and girl of steel in a movie musical. The only thing at risk were their lives.

Yes, it sounds silly.

No, the alternate reality musical did not further the plot much for The Flash or Supergirl, aside from fixing the status of their love lives.

In the grand scheme of the series, it's an unnecessary plot. A way to take advantage of the cast's musical capabilities, and stage a Glee reunion. 

It was also super fun.

Like Barry and Kara, I love musicals. I love the splashy numbers, the ridiculous plots, and the excellent costumes. I've been looking forward to "Duet" since it was announced.

And it did not disappoint.

Cisco: What is it with you and musicals?
Barry: Everything's better in song.

• Permalink: Everything's better in song.

Normally when the shared universes come together, it's because there's a big bad that requires multiple heroes to stop him.

At first, it seemed like that would be the case with the Music Meister. With Kara and Barry incapacitated, Cisco, Wally, and J'onn had to step up. Caitlin played her usual role as doctor, and H.R. remained a cheerleader.

The action on Earth-1 played out in a predictable way from there, but that's okay. Because they saved the fun twist for the final reveal: Music Meister meant it when he said he was all about the love.

As Barry and Kara continued to point out, musicals are easier to live in than real life. The good guys win in the end, and love finds a way.

We watch them because they give us hope. That's why we watch these shows, too. Sure, the action is fun, and the villains can be deliciously evil.

But ultimately, we want to see the good guys win. We want to see Barry and Kara and everyone else on their teams happy. Good needs to defeat evil.

Sometimes, the message doesn't need to be any more complicated than that.

I also enjoyed the Music Meister giving Wally a confidence boost, too.

H.R. was already on the case since those two have a special bond, but Kid Flash needed to remember that he could kick a villain's ass.

His trauma probably won't disappear after one win, but it's a step in the right direction.

Now, as for the musical itself, it was fairly straightforward. All the characters had different names and looked at Barry weird when he used the names he knows.

It's hard to pick which moment was the best.

Barry and Kara's rendition of "Super Friends" may win the award for best duet ever. The two of them radiate adorableness, and yes I'm going to say it, glee.

Cisco, Winn, and the Music Meister teaming up for "Put a Little Love in Your Heart" was the runner up for best song in my book.

Love will find a way. You can do it! Power of love and all that.

Music Meister

• Permalink: Love will find a way. You can do it! Power of love and all that.

I do think it may have been a bit of a gamble to assume the audience regularly watched both shows. 

While Supergirl Season 2 Episode 16 did heavily focus on Kara's relationship with Mon-El, and what led to her heartbreak, people who don't watch both shows may have been lost during their story.

As someone obsessed with Kara and Mon-El's relationship, I loved watching him step up to help save her. I'm happy she forgave him (don't screw it up, Mon-El!).

But it still seems like an odd moment to happen on a show other than Supergirl.

Thankfully, Barry and Iris also received a second chance.

It still doesn't make much sense to me why Barry decided to end their engagement in the first place.

But I think we can all agree that Iris deserves a swoon-worthy proposal without a dark cloud hanging over it.

Barry more than delivered.

Even if we didn't know Grant Gustin could sing, doesn't Barry feel like the kind of guy who would belt out a tune for his true love?

I found it funny that aside from Caitlin, none of Barry's friends knew he could sing. Because someone who loves musicals as much as Barry would definitely be bursting into song at random moments.

Watching Barry serenade Iris felt right in the best, most emotional way. And this time, we got to see Iris accept.

Now it's your turn to tell us what you thought of "Duet."

Were you surprised by Music Meister's true motives? Did you enjoy Kara and Barry's movie musical? Are you happy to see Barry and Iris back on track? Which song was your favorite?

Remember, you can watch The Flash online anytime!

Mandy Treccia was a staff writer for TV Fanatic. She retired in September 2017. Follow her on Twitter.