“Mr. & Mrs. Mxyzptlk” is episode thirteen of season two of Supergirl.
At the end of the previous episode, “Luthors”, Kara was finally admitting to Mon-El that yes, she did have feelings for him, and they were about to kiss – when something zipped around the room and formed itself into a man who announced that he was Mr. Mxyzptlk and he loved her. Calling her Kara Zor-El.
This episode opens immediately after that. Mr. Mxyzptlk decides they need candles, music and flowers, snapping his fingers each time and many candles, a quartet and lots of flowers appear. The last thing they need is a ring. Which also appears and Mr. Mxyzptlk asks Kara if she will marry him. Mon-El, probably upset about the moment being interrupted, grabs Mr. Mxyzptlk and tells him that Kara is with Mon-El. Mr. Mxyzptlk doesn’t consider Mon-El worth noticing. When Mon-El tries to punch him, Mr. Mxyzptlk disappears – then causes Mon-El to appear at the DEO without all his clothes.
Kara doesn’t know who Mr. Mxyzptlk is or how he got there. He explains that his name is spelled like it sounds and causes it to appear in floating blue letters. Kara probably doesn’t want to be married to someone called Mxyzptlk – not if you had to take his surname. Mr. Mxyzptlk then puts her in a wedding dress, to which she objects. Even if it is Vera Wang. Mr. Mxyzptlk claims to be enthusiastic and to have watched Kara across the dimensions. He says he may be all-seeing and all-powerful, but he cannot force Kara to marry him. Along with a few other things. Such as drink orange juice. Mr. Mxyzptlk decides Kara is playing hard to get and promises to wow her until she becomes his mate.
J’onn knows that Mr. Mxyzptlk is a fifth dimensional being but has only seen them on Mars, not Earth. One moved a mountain range. They have the ability to alter reality on a whim. Mon-El is also familiar with them; on Daxam they had a zero-tolerance policy towards fifth dimensional beings. Even if they do know how to party. J’onn is sending a Valentine’s Day message to M’gann on Mars; Mon-El asks about the Day of Valentine. He and Kara would both like to get back to what they were doing. First Kara needs to get rid of Mr. Mxyzptlk.
Alex is with Maggie, who thinks Valentine’s Day is dumb. Alex agrees with her – but it looks like she’s lying. Winn is in the alien bar, where he almost gets beaten up by two aliens. But is saved by an alien girl who violently takes them both down. Winn is familiar with her planet and she asks him to have dinner with her tonight. Because she did save his life after all.
Mr. Mxyzptlk then aids Kara with some jewel thieves – and would have killed them with their own guns if not for Kara. One politely thanks her. Win has found lots of records of fifth dimensional beings – genies, jinn, leprechauns. Mon-El wants to crush Mr. Mxyzptlk. Kara doesn’t want that violent a solution. Which causes an argument. J’onn asks Winn to look through alien artefacts to see if there’s anything that would help.
Alex thinks that Mon-El is jealous. Kara doesn’t, but Alex is probably right. Alex wants advice for Valentine’s Day, and explains that Maggie isn’t interested. Kara suggests celebrating it their own way, and wants to know what Maggie likes. Guns. Kara would like other options. Scotch, tiramisu and bonsai trees.
Outside the apartment there’s trouble when the Parasite – the dead Parasite – from “Changing” appears. Mon-El shows up then what appears to be Superman. Except it’s Mr. Mxyzptlk again, dressed as Superman. Kara and Mon-El argue again – and it seems that Mon-El knows how Mr. Mxyzptlk can be sent back. Not that it’s something someone else can do. Mr. Mxyzptlk wanted to show Kara that he could help when villains pop up. Because he made Parasite appear. If Kara doesn’t say ‘I do’ things will go very badly for her world. Great, a psycho suitor.
Kara and Mon-El wind up having another argument; he thinks that she isn’t always a good judge of what she can handle. He thinks she is holding him and Mr. Mxyzptlk to different standards. Which Kara says she is – she expects Mr. Mxyzptlk to behave badly and expects better of Mon-El. Another conversation that did not go well.
Afterwards, Winn asks Mon-El for advice on a girl issue. Things were easier for Mon-El on Daxam when he objectified women and didn’t care for anyone. Not terribly useful advice. Winn also has a bunch of artefacts he dug up, one of which radiates fifth dimensional energy. Whose case he leaves open as he heads to dinner with the alien girl, Lyra. Naturally, Mon-El takes it.
Alex’s Valentine’s with Maggie does not go well. Maggie had a very bad experience and hadn’t told Alex everything. Mon-El tries to deal with Mr. Mxyzptlk himself. Kara has to figure out some way of sending Mr. Mxyzptlk back – because otherwise he might break the planet.