Wow. Just... wow.
When I first heard that "Rarity Investigates" would be happening right after "Canterlot Boutique", I questioned the decision to have two Rarity episodes back-to-back. Traditionally, characters have their episodes spaced apart so as to give other characters a fair chance to shine. Now, if I had seen the previews for this, I would have known that it's also a Rainbow Dash episode, but at the same time, it's not often that a character has two episodes in a row. This was my primary concern going into the episode, not entirely sure what it was about.
And then Sassy Saddles appeared.
At that point, I immediately paused the episode. Did that just happen? Was My Little Pony actually having continuity between episodes? If there was one complaint that I'd had about the past couple seasons, it was a distinct lack of character progression. The revelation that the previous episode's events would have an immediate effect completely shattered that. But maybe this was just a glorified two-parter. I mean, "Canterlot Boutique" seriously impressed with its character progression, but surely this episode was just building off the preceding events. And then Rainbow Dash appeared.
She said she was there to fly with the Wonderbolts in case one of them couldn't make it. At that point, I knew. It's happening. After years of this show growing increasingly stale, it's finally happening. The character development that's accumulated over the past few years it finally having a direct influence upon the show itself. Even at the show's height in the second season, I don't think character progression has had quite this concrete of an impact on the show.
But what about the plot, you might ask? It's great. For the first time, the spotlight is shared by Rainbow Dash and Rarity, and their dynamic is so excellent that one wonders why they haven't shared an episode before. Unlike the over-abundance of episodes which Rarity shares with Applejack, the friendship between the two ponies is clear in every moment. Rainbow soon finds herself in trouble after she's framed for tricking Spitfire into leaving to help her allegedly ill mother. Rarity immediately offers to help, and her methods are unique to her interests.
Rarity herself takes on a detective role while entertaining noir fantasies, resulting in an entertaining blend of fashion-oriented sleuthing and smooth monologues. Very few episodes have gotten her wrong, but this ranks up there as some of her best characterization ever. Given a different focus from the usual stories of dresses and celebrity, she proves to be just as entertaining as ever, and although Rainbow can't see it, there's a strain of logic to her using her own knowledge for the investigation. This is a clever twist on a concept that was done, albeit with less consequence, in S2's "MMMystery on the Friendship Express", allowing Rarity's unique personality quirks to shine while still letting her solve the mystery in a competent way.
Once the opening revelations are out of the way and the plot is in motion, it relaxes a little bit. This isn't exactly something with the depth of "Amending Fences", but it is, by some measure, the best-paced episode since "Slice of Life". After the recent string of episodes that felt constrained by the running time, it's refreshing to see one that fits it so comfortably and effectively. There's a variety of fun scenes to be had here, relying on the wonderful dynamic between Rarity and Rainbow Dash as well as on the fantastic script. Whether the conversation involves Royal Guards, the Wonderbolts, or some popular cake maker, the dialogue is always exciting.
As I've said previously, I'm not a fan of the direction Rainbow Dash is being brought in. I don't mean her increasing standing with the Wonderbolts, but the fact that she's rarely had a chance to stand as a truly strong character lately. To an extent, that's still the case here, with Rainbow Dash being in trouble and basically relying on someone else to assist her. However, without spoiling, there's an event near the end that basically removes that complaint as well. With Rainbow currently being framed for something and not really being a brilliant detective, needing help is understandable, and any complaint to be had with her passivity is removed once she gets her own chance to shine.
Also of note are the excellent visuals. In many scenes, there's a noir-esque filter that sets the scene in monochrome and puts light shadows in the corners. This combines with some really smart lighting to result in a particularly fantastic looking episode, which also helped by great designs for the characters and settings.
But honestly, even if it weren't as enjoyable an episode as it is, the various ways in which this episode moves the show forward would be more than enough to impress. I mean, this level of character progression and continuity is nearly unprecedented, and having a previously unexplored character teamup is also a delight. Season 5 has been all about trying different sorts of fresh new things, but "Rarity Investigates" puts the rest to shame by doing things that are not only new and different, but which actively push the show forward, and it's a thoroughly enjoyable episode on top of that. Just brilliant.