A few stories were dedicated to Rina's attempts at proving that Meimi is St. Tail and Meimi trying to convince her of the opposite. How did that ended? Well, Rina had finally caught St.Tail and showed her face to Asuka Jr... Only to freak out when she touched St.Tail's manly moustache! Expecting to be caught, St.Tail had knocked out a burly and moustached male cop and dressed him with her costume and a wig for a last-minute swap, so she'd convince Rina that St.Tail was a male, and traumatized both her and Asuka Jr. in the process. She later explained what she had done to Asuka Jr. because she felt sorry for him, but Asuka Jr. went on saying Rina that St.Tail was a male...
Anime only: Asuka Jr. had been taken off the case and replaced with a special officer who used electronic trackers to chase Saint Tail. As Saint Tail is committing a heist, Rina is bugging her uncle the mayor to get Asuka Jr. back on the case, but the mayor replies that by then the special officer must have already caught Saint Tail... Cue the special officer breaking in the room, accusing Rina of being Saint Tail (cue hilarious WTF face) and starting throwing each other across the room, with the mayor and the officer's sidekick wondering what the hell is happening and Saint Tail's pet hedgehog (that had brought the tracker there) laughing its ass off. Needless to say, Asuka Jr. got back the case by the end of the episode.
The prequel manga chapter showing how Meimi first met Seira and Asuka Jr. and started going around as Saint Tail.
How Seira realized Meimi could help her recovering the stolen key of a confessional? Easy: Meimi couldn't resist the temptation to perform and summoned a kangaroo dressed with a tuxedo, and Seira (and the kid who would be peer-pressured into stealing the key) saw her.
Asuka Jr. had found out about the kid stealing the key because his friends would otherwise call him a coward for saying he had seen a kangaroo with a tuxedo. Asuka Jr. told him that doing something like that was the mark of a coward, and that kangaroos don't wear tuxedos... Cue him witnessing an horde of tuxedo-wearing kangaroos. Dancing.
When the still unnamed Saint Tail has left, having recovered the key, scared the kid into not doing it again and showed Asuka Jr. that stage magic is not mere tricks and scamming (previously Asuka Jr. had claimed this in class, and Meimi obviously took offence), the kid had marked her as a Phantom Thief, and Asuka was crying in despair because he couldn't understand what had just happened.
The day after, Seira shows Meimi the school journal with a bad picture of her (presumibly taken by Asuka Jr.) dubbing her a Phantom Thief, and, in an instance of Sure, Let's Go with That, told her she would go by Saint Tail and steal stolen things and give them back to their legitimate owners, and that she would pass her the information in the confessional whose key had been recovered by Meimi (Seira had kept it to 'reserve' the confessional for themselves). Seira is smiling all the time. Meimi is less than amused.
How did the chapter end? With Asuka Jr. reading about kangaroos to make sense of Saint Tail's trick while his father threatened to disown him if he tried to breed kangaroos.
In one occasion, Saint Tail wrote her 'burglary warning' on Asuka Jr.'s face while he slept. His reaction when he saw it in the mirror made it even funnier: first he freaked out, then... "I'm not washing my face".
Episode 2: a balloon exposed right out of the school.
Episode 3: Asuka Jr. has been caught sleeping in class, and is forced to read out loud from the book... And reads out loud Saint Tail's message snuck in the book. After a few seconds of silence, Asuka Jr. realizes what he had just read and freakes out;
Episode 4: as detailed above, it was written on Asuka jr.'s face;
Episode 5: written on the back of a theme park flyer and given to him by Saint Tail dressed as a giant plushie;
Episode 6: an arcade screen after Asuka jr. gets a game over thanks to Rina's dubious help;
Asuka sr. *pissed, at the theft victim*: "Well! What is this all about?! Shall we hear your explanation?!"
It was present in the first manga chapter too, but the absence of the police made it less funny.
How did Meimi get permission to buy and keep her pet hedgehog Ruby? Easy: she proposed the name Ruby after her mother's engagement ring, and took advantage of her parents' attack of romanticism.
About Ruby... Meimi's crush on him. To her, going at the pet shop to see her was a date (her words).
From that same episode... Meimi's hedgehog-themed trick. She was so crushed when the villain bought Ruby before she could and made the hedgehog eat a diamond... And really happy when she found out the latest caper involved stealing Ruby.
Asuka Jr. and the villain were chasing Saint Tail, and at one point they were on an elevator and Saint Tail on another next to it, and capable to see in the other. Asuka Jr. mentally begged for Saint Tail to turn so he could see her face... And she did, hiding the face with Ruby while blowing a raspberry at them, before saying bye bye: her elevator stopped, theirs went on.
In episode 5 and the manga chapter it's taken from, Asuka jr. meets Meimi after receiving a note from Saint Tail. He talks to her about the clocktower with statues that bring happiness to couples that see them, Meimi wonders if he's going to ask her out, and then...
Asuka jr.: "Is it true that they're very expensive?"
Meimi: "I suppose so..."
Asuka jr.: "Why would shenote Saint Tail. Asuka jr. misunderstood the note and believes she's going to steal one of the statues do something so villainous?! I got it. Never mind, see you!"
Rina's debut, from her failed attempt at helping Asuka jr. with a game at the arcade to him noticing she's One Head Taller.
Even funnier in the anime, where Asuka jr. decides to run away to plan to capture Saint Tail after a warning received from the Game Over screen of the arcade game and Rina gives chase to find out who Saint Tail is (she has just arrived in town). He refuses out of spite, but Rina convinces him thanks to her very persuasive Octopus Stretch and Boston Crab.
During Saint Tail's caper, Rina butts in with the excuse her family has loaned paintings to the targeted museum. At one point as they chase Saint Tail, Rina reveals she lied... And Asuka jr. ends up hitting a wall face first before declaring that Rina is a thief because she lied