Star and Marco need Janna's help to return to Mewni.
Tropes:
- Cassandra Truth: Janna really doesn't remember how she got to Mewni, at least at first, despite the others not believing her.
- Chekhov's Gun: The trek back to Mewni when the portals are all broken sees several guns going off in sequence:
- Janna's mysterious appearance in Mewni in "Out of Business", which was questioned several times, is the first lead on a way there.
- The missing T-shirt prize in "Britta's Tacos" was stolen by Janna, and in the process of stealing it, she found a portal to travel to the Magic Dimension.
- The sealed well of magic that Star and Moon encountered in "Conquer" turns out to be a well on the basement of Britta's Tacos and connects the Magic Dimension with Earth. This one gets a flashback in case you've forgotten it since Season 3.
- A Day in the Limelight: We see some of Janna's daily routine, though this is along with the plot about finding a way into Mewni.
- Did You Think I Can't Feel?: Though she doesn't show it much, Janna is disturbed about losing her memory of how she got to Mewni, as she likes to create her own weirdness, not to have it imposed on her. She resents Marco's implication that she's just messing with them.
- Gag Echo: When Star wonders where Janna is, Marco says she's probably somewhere weird, like a monster truck junkyard. When Star calls Janna, that's exactly where she is.
- Gang of Hats: Janna regularly makes back-alley trades with a gang based around knitting, whose leader is named "Needles" (as in knitting needles, not syringes). One of them is seen making Counterfeit Cash out of yarn.
- Hypocritical Humor: After the gang barges into her room, Janna complains that the guys aren't respecting her personal space. She then reveals that she put a body cam on Marco.
- Implausible Deniability: When the group stop at Britta's Tacos for lunch, Oskar asks Janna if she is in fact Janna, who's banned for life from the restaurant. Janna nonchalantly says that no, she's Banana. Oskar believes her and serves her order.
- Naked People Are Funny: Tom's clearly not wearing his pajama shirt while he's sleep-floating (covered by his blanket, of course), and Star and Marco's reactions make it pretty obvious that he's not wearing anything else either.
- Portmantitle: Of "Janna" and "Shenanigans".
- Title Drop: Star tells Marco and Tom not to be distracted by Janna's "Jannanigans".
