SPOILER WARNING: This article contains major spoilers for "Duet," the musical crossover between "Supergirl" and "The Flash."
Though the musical crossover between "Supergirl" and "The Flash" took place in a dreamworld, it had very real consequences. Both the Scarlet Speedster and the Girl of Steel have been experiencing some turbulence in their love lives, but -- with a little help from the impish Music Meister -- they managed to resolve that by the episode's conclusion.
Over the course of "The Flash" Season 3, Barry and Iris have struggled with the knowledge that Iris will die at Savitar's hand in May. In an effort to circumvent that, Barry proposed; however, troubled by the idea that he proposed for the wrong reason, Iris broke it off with him, and the two agreed that they needed some space. The Music Meister's dreamworld revealed to Barry that he shouldn't let a love like Iris go on account of something like a misunderstanding when he pleaded to Millie's fathers on behalf of her relationship.
Likewise, Supergirl is upset with Mon-El because he lied about the fact that he was the prince of Daxam. In talking to Tommy's father, Kara realized that Mon-El had lied to her because he was afraid of how she would react when she found out. As such, she became aware of the fact that she was being too hard on Mon-El.
At the end of the episode, Kara and Barry -- both without their powers -- were shot in the gang war between Tommy and Millie's fathers. Cisco was able to vibe Iris and Mon-El into the dreamworld just in time for them to see their significant others dying from their wounds on the street. Of course, with true love's kiss, both Mon-El and Iris were able to bring Kara and Barry back into the real world.
As Kara and Barry came around, Music Meister appeared before them and revealed his ultimate goal: to teach them a lesson about love. He also confirmed that he was from an alternate dimension, but he refused to specify which. He then disappeared into the ether, which leaves the door open for him to return in the future.
Starring Melissa Benoist as the Girl of Steel, “Supergirl” airs Mondays at 8 pm ET/PT on The CW. The series also stars Mehcad Brooks as Jimmy Olsen, Chyler Leigh as Alex Danvers, Jeremy Jordan as Winn Schott, David Harewood as Martian Manhunter and Chris Wood as Mon-El.
Starring Grant Gustin as the Scarlet Speedster, “The Flash” airs Tuesdays at 8 pm ET/PT on The CW. The series also stars Jesse L. Martin, Tom Cavanagh, Carlos Valdes, Candice Patton, Danielle Panabaker, Keiynan Lonsdale and more.