There's no getting around it; Index doesn't end on a high note. For one, it doesn't end so much as just stop running. There's no big series-ending climax, just three more (three and a half more?) self-contained stories and then…nothing. (Until season two, of course.) Add to that the short duration of the remaining arcs—the longest is four episodes—and the side-story nature of most of them and you have a stretch of episodes that feels a lot more like the slightly padded middle of a series than a big finish. Not that it isn't still loads of fun; it just isn't as much fun as we know it can be.

Exhibit number one: the Angel Fall arc. The arc so thoroughly sidelines Index that she might as well not exist and reduces Toma's role to such an extent that in the end you have to ask yourself why he's even there. The story is a lot less involving without them, and specifically without their adorable rapport. It compensates with a greater sense of humor, which sounds rather poor compensation but works better than you might think. The sight of the series' many characters acting thoroughly out of character (Index as Mom? Pervy best friend Aogami as Index?) is pretty darned funny, and is generally enough to distract from the reduced roles the principals are given. The increased focus on the fetching Kanzaki doesn't hurt anything (nor does the inclusion of Toma's previously absent family), and as ever the mechanics of the series' shonen-action plotting are fairly impeccable. The threat posed by Angel Fall is huge and, when the truth is fully revealed, seemingly insurmountable. The true nature of the spell is interesting (especially in what it says about Index's world) and its origin both unexpected and a clever source of emotional tension. Then, quite naturally, the show squanders everything on an irritating cop-out ending.

So it goes for most of these ten episodes. Every arc has its own advantages and disadvantages and every one is in the end less than the series at its best. A single-episode filler tale of Toma playing fake boyfriend for Mikoto has flashes of comic excellence and changes abruptly in the late going from fluff to deadly confrontation, but nevertheless remains a filler episode. The final arc returns full-time to Toma and Index, but centers on a new character and an incidental villain who have nothing to do with the series' central plot (Toma's right hand, Index's head full of magical tomes). There are tasty tidbits throughout—Index tapping into the power of the tomes; a coda that suggests great and possibly unfriendly powers at play in Toma and Index's lives—but the arc is clearly a throwaway side-story. Ironically it's the middle arc, which abandons Toma and Index altogether, that delivers the emotional and visceral punch that the others never quite muster. It's a little gem of an arc, a fast and furious tale that tracks the psychopath from Mikoto's arc as he finds a last, desperate, and potentially deadly chance at redemption in a diminutive clone of his one-time victim. It's smart, morally complex, and occasionally highly personal stuff—in addition to being good, bloody action. It is also, however, only two episodes long.

All of this can make the series sound lumpier than it actually is. Of course it is lumpy in some ways, especially in its pacing, the start-stop motion of which is exacerbated by the second half's shorter arcs. But mostly it goes down slick and easy, providing a well-tuned mixture of humor, emotion and excitement. It isn't just the Angel Fall arc that has the mechanics down pat. No matter how disposable or short or Toma-deficient an arc is, it still works like a well-oiled machine. They establish their characters and relationships, trot out something to threaten all that is good and holy, and put that something to rest in an action blowout (with maybe some surprise revelations and certainly some rhetorical sparring along the way) all with near-scientific precision and efficiency. Hiroshi Nishikiori has the flow and execution of Index's short-arc action storytelling pretty much completely mastered. He wields Yūichi Tanaka's clean character designs and J.C. Staff's expressive animation like emotional weapons and orchestrates action with equal attention to magical (or psychic) spectacle, gut-level thrills, and emotional content. He knows exactly when to save money with shortcuts, when to obscure movement with shadows, and when to bring the action to bright, detailed, fully-animated life. He can time a heroic entrance to nail-biting perfection, and knows exactly when and where to let I've's techno-rock score, well, rock. He shepherds each arc from beginning to generally (though certainly not always) satisfying conclusion with a seamless ease that won't let you stop until the last episode's credits roll.

And yet still only rarely are these ten episodes as fulfilling as the fourteen before them. It's nothing qualitative; just a simple matter of magnitude. Toma's rescue of his dad or Index's friendship with Kazakiri can certainly pluck at the old heartstrings, but nothing breaks your heart the way Mikoto did before the climax of her arc or Index did at the conclusion of hers. Toma devises a couple of decent strategies to take down golem-wielding baddie Sherry, but nothing half so clever or satisfying as the revelatory jumps of logic he used to turn the tables in the series' first few arcs. While Toma's life doesn't exactly stay static, nothing here upends his world the way the end of Index's arc did. When Toma or Kanzaki or Accelerator takes down an enemy it's highly satisfying, but we don't stand up and cheer the way we did when Toma stuck it to Accelerator or utterly destroyed Izzard. If Index is a well-oiled machine, it's a machine that isn't firing on all cylinders right now. Still, even without all of its cylinders firing Index is an entertainment engine to be respected. It's just that having been there when the series was roaring full throttle, it's a bit of a letdown to see it finish on cruise control.